CA2392643A1 - Excavator teeth, apparatus and method - Google Patents

Abstract

Fabricated excavator teeth comprising projections cut from hard, highly abrasion steel plate or bar stock, for example having a Brinell Hardness exceeding 225, and as high as 400 or higher, welded to cores through which the teeth may be connected with excavator apparatus, including any kind of digging implement, such as buckets and ripping arms, and any kind of excavating machine, such as power shovels, backhoes and dredges.

Description

EXCAVATOR TEETH, APPARATUS AND METHODS

3 The invention relates to teeth useful in connection with excavating 4 machines, and to digging implements and excavating machines comprising such teeth.

'7 The teeth commonly employed on digging implements for excavation 8 machines, such as for bucket leading-edges, ripping arms and dredge-9 heads, have a limited service life, depending in part upon the severity of the abrasion to which they ace subjected, Severe applications include rock 11 fracturing and removal, and excavation of frozen earth. in a rock trenching 1'2 operation in Ohio, U.S.A: sandston~ with a very powerful excavating 13 machine having a digging.implement equipped with cast high abrasion 14 ' resistance alloy teeth, service lives as low as less than an hour were experienced. This invention seeks to fulfill a need for improved excavator 16 teeth and excavation methods.
1'?' SUMMARY OF THE INVENTION
18 in one aspect, the invention relates to an excavator tooth useful for 19 fracturing rock strata. It comprises a metallic core having front and rear ends and at least one longitudinal surface extending between said ends.
21 There is also at lea$t one projection formed from metallic stock, which may 22 for example be bar stock of round, square or rectangular cross-section, or 23 more preferably may be plate stock. A projection according to the invention 24 has a tip, which is an end of the projection, of whatever shape, that is intended to act on the rack or other material on which the tooth may be 26 used. Such projection is secured to the core, at least in part by welding, 27 ~ with the tip and at least portions'of the length of the projection{s~
extending 28 beyond the front end of the core. in or on the core there is at least one 29 tooth connector portion, including at least one concave or convex connector surface, of circular or other configuration, positioned and adapted to 1 engage with and non-destructively disengage from at feast one mating 2 surface of an excavator apparatus.
3 The invention has a variety of additional aspects, among which are 4 preferred and highly preferred embodiments. 1=or example, the core may be of circular or non-circular cross-section, and may have a single 6 longitudinal surface in the form of.a cylinder or plural longitudinal surfaces.
7 The at feast one projection preferably includes at least one cut edge, an 8 edge formed at least in part in cutting the projection from the metallic stock, 9 and this edge may for example be an end of the projection when it is cut to length from bar stock. More preferably, the cut edge is a longitudinal edge, 11 for example an edge resulting from cutting the projection from a plate.
12 1t is preferred that the projection metallic stock thickness be about 112 to 13 about 3, or about 314 to about 2 and 114 or about 1 to about 1 and 112, 14 inches. This dimension will correspond, for example, to the diameter of round bar stock or the thickness of plate stock.
18 In a particularly preferred embodiment, the tooth includes at feast one 17 , projection which has vn opposite sides thereof, as viewed in transverse 18 cross-section, at feast two approximately planar surfaces 'which are 19 approximately parallel to one another. Preferably, these surfaces of the projections are approximately parallel to'the digging direction of the.tooth.
21 More preferably, when viewed in transverse cross-section and when 22 positioned vertically in the view, these surfaces are at least about as III
as 23 the distance between them.
24 Prefer~bfy, there are at least two projections on the excavator tooth. More preferably, these are secured to substantially opposite sides of the core.
26 In a particularly preferred embodiment, there are ~at least two projections 27 that have inner surfaces, portions of which surfaces generally face one 28 another and extend forwardly from the core. These portions, as they 29 progress toward their tips, have an angle of divergence between them of 34 about 4 (i.e., no divergence or a small convergence) to about 30 degrees, 1 prefierably about 2 to about 30 degrees more preferably about.l2 to about 2 24 degrees, still more preferably about 16 to about 20 degrees and most 3 preferably about 18 degrees, 4 in another aspect, the projection metallic stock is preferably of abrasion resistant steel having a surface BMN ~Brineli Hardness Number) of at least 8 about 225, more preferably at least about 300, mare preferably at least 7 about 350, more preferably at least about 375 and more preferably at least 8 about 400, at least prior to its fiabrication into teeth according to the 9 invention, and more preferably afiter such .fabrication. , Preferred embodiments of the projection metallic stock comprise iron, 11 carbon, manganese and silicon, and optionally but preferably at least ong 12 additional alloying element selected from the group consisting of chromium, 13 nickel, boron, molybdenum, vanadium, titanium, copper, aluminum, niobium 14 and nitrogen. More preferably,the sulfur and phosphorous contents of the metallic stock are respectively less than about .Q.05,~ preferably less fhan 1fi about 0.04 and still more preferably less than about 0.030 percent by 17 weight of the entire stock.
18 in a preferred embodiment, there is a narrowing of at least one projection, '19 between its generally longitudinal edges, in the direction of the tip, which may for exarrfple occur along a single edge, 21 However, in still more preferred errtbodiments, first and seco~nd~
longitudinal 22 edges of at least one projection, or more preferably first and second edges 23 ofi a plurality of projeckions, converge with one another, along at least a 24 portion of their respective' lengths, in th~ direction of their tip or tips, in a particularly preferred embodiment, such narrowing, or such Z6 convergence, exists at least closely adjacent to the tip or tips.
27 Most preferably, .the projection edges converge, as th~ edges approach the 28 tips, preferably at an angle of about 10 to about 35 degrees, more 29 preferably about 15 to about 30 degrees, still more preferably about 9 7 to about 25 degrees and even more preferably about 2112 degrees.

1 A particularly preferred form of the invention comprises convergence of at 2 least portions of projection longitudinal edges along substantially straight 3 lines, preferably closely adjacent to their tip or tips, 4 Preferably, convergence occurs over at least about 25% and more preferably up to at least about 100% of th~ length of the projection 5 longitudinal edges ? Preferably, the projection or projections respectively include two convergent 8 edges that. are cut edges.
9 It is preferred that at least one projection be secured to the core through at I~a~t one longitudinal surface of the core. Advantageously, the projection 11 or projections islare secured to the core preferably entirely, by welds.
Iri a 12 partict~tarly preferred embodiment, said at~least~one longitudinal surface 13 has a plurality of projections secured thereto at least in part by welds 14 between the at least one surface and adjacent portions of the projections.
. The tooth connector portion may be located at the r~ar end of the core, 1 G preferably in or on a rearmost surface of the core.
17 Wherever located on~ the core, the tooth conn~ctor portion may be securely 18 connected with a mating~surface of an excavator apparatus. Inca preferred 19 embodiment,~the tooth connector portion is a female member ext~nding into the rear end of the core and the mating surface is a male member on 29 an excavator apparatus, or vice versa.
22 A locking member may be present, e.g., a resilient insert or metallic pin, to 23 engage the tooth and a portion of the excavator apparatus, thus providing 24 security for the connection between the tooth connector portion and the mating surface.
26 According to the invention, the excavator apparatus may be any excavating 27 machine adapted to carry, in working position, one or more teeth 28 constructed according to the invention. Such excavator apparatus may for 29 ~xample be an excavating~machine selected from the group consisting of gage 4 1 power shovels, backhoes, draglines, dredges, graders and bulldozers, or 2 may be a digging attachment or combination of attachments adapted to be 3 ~ mounted on an excavating machine and to carry, in working position, one 4 or more of said teeth.
In one particular embodiment, they excavator tooth is connected with a 6 bucket having a mounting pin for connecting the bucket to an excavating 7 machine. T'he tooth has a projection with a major surface which is held in 8 approximately perpendicular relationship with the longitudinal axis of the 9 mounting pin. . , 1~0 Another embodiment includes an excavator tooth connected with a rack 11 ripping tool having a mounting pin for connecting the tool to an excavating 12 machine. Here, the tooth has a projection with' a major surface which is 13 held in approximately perpendicular relationship with the longitudinal axis of 14 the mounting pin. ~ ~ ' Still another embodiment comprises an excavator tooth connected with a 1 fi bucket or blade at a substantially rectilinear cutting edge of the bucket ~or 17 blade. That edge is or has a digging axis, and a major surface of the tooth 18 is held in approximately perpendicular relationship with that axis. 'On the 19 other hand, the bucket or~blade may have an at least partly non-rectilinear 2g cutting edge having ends at sides of the bucket or blade. In which case, an 21 imaginary line connecting those ends defines the axis.
22 In yet another embodiment, an excavator tooth is connected with digging 23 end of a pivotable ripping arm for an excavating ~machin~. This arm has a 24 pivoting axis about which ~e arm swings in operation. A major surface of 28 the tooth is held in approximately perpendicular relationship with the axis.' 26 Other aspects of the invention includes methods of~axcavation. Among 2T these are a method of excavation with an excavating machine having an ~8 arm with a pivot affording angular movement of an end of the arm about a 29 central axis of the pivot, said arm supporting and delivering digging force 3D and motion to a digging implement having projections. This method 31 comprises applying such force through projections that are formed of cut 1 ~ plate stock and have major surfaces that are approximately perpendicular 2 to said axis.
3 The invention also includes a method of fracturing rock or frozen earth with 4 an excavating machine Having an arm with a pivot affording angular movement of an end of the arni about a central axis of the pivot, said arm fi supporting and delivering digging force and motion to a digging implement 7 able to apply sufficient force through the tips of projections on said 8~ implement to break up the. strata. This method comprises applying such 9 force through projections that are formed of cut plate stock and have major t0 surfaces that are approximately perpendicular to said axis.
11 optional but preferred embodiments of each of the foregoing methods 12~ include applying such force .through teeth having edges that converge at 13 angles as above described, andlor applying such force through teeth 14 respectively having two projections with inner major surfaces~generally facing one another and having an angle of divergence between them as 16 above described. Still other optional but preferred embodiments of each~of 17 the foregoing methods comprise applying such force through teeth wherein 18 the plate stock is abrasion resistant steel plate having a surface 8HN as 19 above described andlor having a compo$itian as above described., , Cther embodiments of the invention are described below, and additional 21 embodiments of the present invention, not disclosed herein, can be 22 constructed by persons skilled in the art without departing from the spirit of 23 the invention.

This invention makes available improvements in excavator teeth. Most 28 embodiments of the invention will include one or mare of the following 27 advantages. Certain preferred embodiments will include all of these 28 advantages. As compared to common, cast, replaceable steel teeth used 29 in the past, it is possible for persons skilled in the art of steel fabrication to fabricate excavator teeth according to the invention which exhibit excellent 3't cutting praperkies, long life in rock excavation and other applications, 1 reduced cost for teeth per hour of operation and ease of fabrication, Cne 2 can fabricate~embodiments that afford a strategic balance between service 3 life and ease of penetration of rocky strata. Moreover, the invention offers 4 . the possibility of providing a range of satisfactory products which offer a degree of flexibility with respect to this balance. Where the projections 6 , have approximately parallel sides, then, for 'a given cutting edge width, the 7 invention provides improved bending resistance in the projections, as 8 compared with teeth having projections formed from round bar stock. The 9 methods of the invention offer the operational advantages set forth above.
Cther advantages of these excavator teeth and methods will become 11 apparent to those skilled in the art upon using the invention.
12 BRfEF DESCRIP~'IQN Oi= THE DRAWINGS
13 Figure 1 is a side view of an excavator tooth according to the invention.
14 Figure 2 is a top view of the excavator~tooth of figure 1.
Figure 3 is a view, in perspective, of'another embodiment af'the invention 16 having a core which is the remnant of a cast excavator tooth from which the 1? original teeth have been worn away.
18 Figure 4 is a side view, partially in section, of yet another embodim~nt of 19 the invention having two projections, a portion of a prajectlon in the foreground being broken out to reveal a projection in the background and 21 parts between them.
22 Figure 5 is a perspective view df ~stili another embodiment of the invention.
23 Figure 6 is a side view, partially in section, of the embodiment of figure 5, 24 but with the addition, in phantom outline, of a portion of an excavator apparatus.
28. higure 7 is~a perspective view of a digging~impl~ment, i.e., a ripping arm, aving mounted on its end an excavator tooth as a shown m figures 1 and 28 2.
P$ge 7 1 Figure 8 is a perspective view of a digging ii~nplement having thereon a 2 ripping arm and excavator tooth as shown in figure 7.
3 Figure 9 is a perspective view of a digging implement having thereon two 4 ripping arms, respectively.having excavator teeth as shown in ltgure 7..
S Figure 10 is an end view, with portions broken out, -of a dredge cutter-head.
6 Figure 11 is a perspective vi~w of 2~ digging implement, i:e., a bucket, 7 . having a rectilinear front edge provided with a row of excavator teeth 8 according to the invention.
9 Figure 12 is a perspective view of a digging implement, i.e., a bucket, having a non-rectilinear front edge provided with adapters and with 11 excavator teeth according to the invention; two of five teeth being left Off of 12 their adapters to simplify the view. . . .
13 Figure 13 is a side view of a backhoe unit including a~ripping arm equipped 14 with one or more excavator teeth according to the invention.
. Figure 14 is a side view of a power shovel including a ripping arm equipped 9 6 with at .least one excavator tooth according to the invention.
1 ~ Figure 15 is a side view of a dragline unit including a bucket having 18 excavator teeth according to the invention.
'l9 Figure 16 is an enlarged portion of fgure 15 providing greeter detail with respect to the bucket. w 21 VARIOUS AND PREFERRED EMgODtMENTS
22 Gores may be formed of any suitable metal. Preferably, the metal of the 23 . core should be readily weldable, economir~i and of adequate durability, for 2~~ example, crack resistant, ductile, reasonably hard, strong and tough, in genera(, such metal will be chosen from among one ~or more alloys 26 including one or more alloying elements to promote one or more of the 27 properties of wear resistance and fracture resistance, more preferably Page ~

1 alloys that contain iron as a major component (more than 50°~) by weight.
2 The cores may have arrd preferably do have less wear r~sistance than the 3 projection(s). Wear resistence should be sufficient to maintain, in rock 4 excavating service, the structural integrity required to s~curely support the excavating projeCtion(s) and pertorm their connecting function over the fi useful life of the projection(s), 1 Fracture resistance should be sufficient to resist breakage of the care under 8 the loads imposed in rock excavating service. Rack excavating service 9 includes, far example, one or to more of the following: use, on buckets or other digging implements attached to the amps of backhoes engaged in 11 digging rocky soil or gravel; more preferably, use on drag-fine buckets 12 engaged in the stripping of froaen earth andlor rocky overburden; and, most 13 preferabljl, service on buckets or- other digging implements attached to the 14 arms of large and very powerful hydrauIic shovels, for example, Caterpillar model 385, engaged in the fracturing and subsequent removal, e.p., 1 fi digging, of rock strata. The fracture resistance requirement depends on 17 loads which are sustained in operation, which to some degree depend on 1$ force exerted by excavating rnachlne, the hardness of the rock to be.
19 penetrated by the tooth and leverage imposed on the core by the design of the tooth, for example leverage' imposed by the lengths of the core and the 21 proj~ction(s). ' 22 Temper resistance can also be a bene~cial~prapecty, such as when it 23 assists in warding off to same extent lass in hardness~arising out of heating 24 of the care during welding of the projections to the core or during frictional engagement with rock when the tooth is Iri use.
26 Qne example of suitable metals for the core is carbon steel conforming to 27 ASTM~ Standard A~2~, preferably grade TO~fi. Because of their low cost 28 and ease of welding, these are considered best for applications in which 29 the core will not be subjected to heavy abrasion, such as where only softer 3~ rock is to be fractured and or the projections extend far beyond the fronts of 31 the cores, Where greater abrasion resistance is needed, it is considered 32 best to use cast steels conforming to AISI 8630 or ASTM A148, preferably 33 grade 90-fi0, either of which type of material has been quenched and 1 tempered to any suitable hardness lev~f, for example a BHN of about 300 2 to about 400. Other suitable core metals include, for example, the 3 remnants of worn, cast rock fracturing teeth, such as those manufactured 4 by Mensley and others.
.Approxim2~te. compositions of a number of these core metals, by weight, the 6 balance being iron, appear below:
7 Metal C 11I n P ~, Vii, ~ ~,i, Mo Cu V g!.
8 80-fi0 .32 1,5 .05 .05 .45 .4 9 $fi30 .3 .8 .03 .03 .23 .5 .55 .2 Hensiey .28 .64 .02 .01 1.2 1.7 .2 .4 .04 .02 .03 11 Other .31 1 .02 .01 1.2. 2 .05 .45 .02 ,Q1 .01 12 The specific examples of metals set forth above appear sufficient iri .fracture 13 resistance and temper resistance arid the other properties enumerated 14 herein far purposes of making cores. However, it is believed that there is a wide variety of other'-suitable metals and that persons skilled in the .
16 metallurgical arts are able to adust metals composition and heat treatments 17 ~ applied to such other metals to achieve desired levels of weldability and 18 durability to produce acceptable cores. For further guidance on effecting 19 desired levels of hardness, fracture resistance, temper resitance and other beneficial properties, see U.S. Patents 5,525,167 and 5,595,614 and other 21 patents identified therein, the disclosures of all such patents being 22 incorporated herein by reference in their entireties.
23 Gores may be formed as one or more~castings (single casting preferred) or 24 . as a fabricated assert~bly of segments of plate or non-plate components or in any other suitable way from any suitable new (virgin or used metal not 26 previously employed as a tooth core) or used (previously used as a portion 27 of a tooth) material. Ex2~mples of used materials include the remaining 28 shanks of tooth from which the projections have been worn away. Used 1 cores are not preferred, due to expectation of undependable supply.
2 However, used cores,, where available, can be made into teeth better than 3 the originals.
4 Preferred embodiments of cores have front ends that include front surfaces of any workable shape, rear ends irvith any shape consistent with the E connector function, described below and a longitudinal, axis. The 7 longitudinal surfaces) of the core may have a surface or surfaces of any 8 number or shape, including one (e.g., cylindrical) and plural (e.g., three or 9 . more) (four preferred). As viewed in transverse cross-section, the core's exterior surface may be of any shape, symmetric or asymmetric, for 11 example, imay be at least partly circular, oval, triangular, square, 12 rectangular, diamond, polygonal, parallelogram, trapezoidal, modifications 13 of any af'the foregoing, composite shapes (combinations of the abave)~ e.g.
1~4 generally square but with rounded comers. Such cross-section may be uniform yr variable along its length, but is preferably flattened on two sides 1 G where two projections are wrelded to it. The longitudinal cross-section of 17 the core's exterior surface may have 'any suitable 'shape, may be uniform or 18 variable along its length, may be tapered, at least.iti part (preferred), may 19 hav~ divergent ~land(s)" on which to weld divergent projection(s), when divergent projections are used and may be non-tapered.
21 Teeth fabricated according to the invention have one or more projections) -22 ' which may for sxample be fabricated from metallic stock, such as bar stock, 23 but preferably from plate stock. The metallic stack has a composition 24 andlor trEatment history contributing to -the presence, in the stack,' of properties of wear resistance, fracture resistance and temper resistance 25 sufficient for satisfactory fabrication of and service in excavating teeth, 27 Preferably the metallic stock is abrasion resistant steel, having a ' 28 ~ composition and treatment history being sufficient to provide in the stock a ~29 surface BHN (Brinell Hardness Number) of at least'about 225. Still more preferably, the metallic stack is an abrasion resistant quenched and 31 tempered steel alloy which comprises iron, carbon, manganese and silicon, 32 and optionally but preferably at least one additional alloying element 33 selected from the group consisting of chromium, nickel, boron, 1 molybdenum, vanadium, titanium, copper, aluminum, niobium and nitrogen, 2 the amounts of the aforementioned constituents and the treatment history 3 of the stack being sufficient to provide in the stock a surface BHN of at least 4 about 300, more preferably at feast about 350, still more preferably at least about 375 and most p.referabiy at least about 400. Most preferably, the 6 sulfur and .phosphorous contents of the stock are respectively less than 7 about 0.05, preferably less than about 0.04 and stiff more preferably less 8 than about 4..030 percent by weight:of the entire metallic stock.
9 Preferably, the wear resistance, fracture resistance and temper resistance t0 of the projection metallic stock and resultant projections are sufficient far 11 the projections to remain useful for fracturing rock, while avoiding major 12 breakage of the projections and retaining at least about 50, at least about 13 70 or at least about 85%-of their as-manufactured hardn~ss, in rock 14 excavating service, over a period ~of at least about 4, more preferably at . least about $, and still more preferably .at least about 1 fi and most 16 preferably at least about 40, hours of operation. In some instanc~a, where 17 a particular projection of very hard metal tends to be quite brittle, a 18 workable tooth may be manufactured by using metallic stock having less 19 hardness.
Suitable metals are available, including for example USS (~Inited States 21 Steel) AR 225, AR 350; AR 400 and AR 500, tJSS T~1 and USS T-1, types 22 A, Band C, and USS Ni-~r~Mo; Lukens Hardwear (tm) 235, 400, 425 and 23 500; Bethlehem AR 235, RQC, RQAR, RCA, RQB and RQ; Astra(lay-V;
24 and Oliver !=ormable 400 and Ultra-Tuff plate: Particularly preferred are plates identified as Hardox 4Q0 and especially Hardox 504, respectively 25 having the following reported properties:

1 Hardox 400 Hardox 500 2 (about) (about) ' 3 BHN hardness 360-440 450-580 4 yield strength 145 ksi 190 ksi .

tensile strength 180 ksi 225 ksi 6 elongation (A5) '! 0Id 8/a 7 impact properties 8 (Charpy V, longl-9 tudinal specimen) 18 ft.~ ibs. (at 18 ft. Ibs. (at -40F) +14F) Materials of higher hardness levels may be used.
l 1 The above illustrative metals are believed sufficient in fracture resistanc~, 12 temper resistance and other 'properties enumerated above to be useful in 13 making projections for use in the present invention. However, it is believed 14 that a inride variety of other suitable metals is available and that persons skilled in metallurgy can a~dust metals composition and heat treatments 16 applied to such~other metals to achieve desired levels of weidability and 17 durability to produce acceptable projections. For~further guidance on 18 effecting desired levels of hardness, fracture resistance, temper resitance 19 and otherb~neficial properties in projections, see U.S. Patents 5,528,187 and 5,595,614 and other patents identified therein, the disciasures of alf 21 such patents being incorporated herein by reference in their entireties.
22 Projections of any acceptable thickness can be employed, far example 23 about 1I2 to about 3 inches, frequently about 3I4 to about 2 and 114 inches, 24 and in many instances about 1 to about~1 and'/z inches, most preferably Z5 about 1 and 1l4 inches for the applications. with which the most experience 2G has been acquired.
27 As the tips of projections are brought to bear on rock, sufficient force must 28 ~ be applied in order to penetrate the rock: Otherwise, the tips will only rub 29 across the surface and no fracturing or "digging" will occur. More powerful ~quipment is able to supply more force per unit of tip area; which of course, 1 all other things remaining equal, is a function of thickness. Thus, in teeth 2 for use on more powerful equipment, thicker metallic stock may be used in 3 making the projections, and longer wear would be expected from thicker 4 projections. However, the tips of narrower projections made from thinner metallic stock would be expected to enable a given piece of equipment to G exert mare force-per unit area oil the~rcck strata, and thus penetrate the 7 strata more easily. Accordingly, it is beneficial to select projection 8 thickness with the goal of effecting a balance between service life and ease 9 of penetration. For applications in which ripping arms bearing one or two 1 Q teeth comprising a total of two to four projections made from plate stock are 11 employed on a large power shovel, such as a Gaterpiilar 385, a plate 12 thickness of about 1.25 inches is presently considered optimum. It should 13 be noted that it can be necessary or desirable to adjust characteristics 14 other than projection thickness vVhen preparing teeth far more and less powerful excavating machines.
18 Monolithic projections are preferred. A monolithic projection is composed 17 substantially of a single thickness of a given portion of metallic stock.
18 The projections have "major surfaces". Iri the case of projections formed 19 from plate stock, the major surfaces are thane portions of the projections that, if not surface-modified after cutting from the pfate,~ were otiginaliy part 21 of the largest surfaces of the plate stock, i.e., the top and bottom surfaces 22~ as distinguished from the edges; and it is for this reason that they are 23 r~fer~ed to as "major" surtaces. In the projections, these major surfaces are 24 usually and preferably, but hot necess~riiy; of larger area than any of the other surfaces, i.e., than the peripheral edges, of the projections. In the 26 case of projections cut from bar stack that has approximately planar ' 27 surfaces vn opposite sides thereof that are approximately parallel, and 28 preferably also in the ease of protections cut from plate, the major surfaces 29 are preferably those that are approximately parallel ~to the digging direction of the tooth. Approximately planar, as applied to bar stock, means~at feast 31 nearly flat (i.e. essentially fat ar, if its surface is arcuate, having a radius of 32 at least 10, preferably at least 15 and more preferably at least 20 times its 33 width) throughout at least 80, preferably at least 90 and more preferably at 34 least 95 percent of its width. Approximately parallel, as applied to opposed 1 surfaces of a bar, means nearly parallel, i.e., with an angle of up to 20, 2 more preferably less than 10, still rr~ore preferably less than 5 and most 3 preferably sera degrees between those surrtaces. Approximately parallel, 4 as applied to the relationship between a digging direction and a surface of a projection, means that surtace is more nearly parallel than perpendicular to 6 that direction, more preferably at an angle to one another that is up to 7 about 35 degrees, more preferably up to about 25 degrees, still more 8 preferably up to about 15 degrees and most preferably about 9 degrees nr 9 less, including zero degrees.
1 g Preferably, in the f nished tooth, the abrasion resistance of each projection 11 intermediate its major surfaces is at least a major fraction of its abrasion 1 Z resistance at its major surfaces; ,preferably, the hardness of the projections 13 intermediate their major surfaces is at least about 60, about '~0, about 80, 14 or above 90, percent of its major surface hardness: w Qne or more cut edges are present on projections cut from plate. Two or 16 mare edges may be cut from plate stock. However, one or more edges 17 may correspond to the edge of a plate and thus will not be cut from the 18 plate. Plate stock is preferably' cut by an automatically guided gas jet 19 cutter. For many of the available types of plates, their manufacturers recommend pre-heating prior to cutting and give specific recommendations 21 as to temperature limits. These should be considered.
22 Projection edges may be of straight, curved, saw-tooth, stepped or other 23 configuration(s), and the comers of the projections may be rounded, ' ' 24 chamfered, or not. Preferably, there will be at least two edges having ~5 portions that converge to a tip. Convergence may be along straight, curved 2f or other farms of axes to provide dagger shape, "hook" shape or any other 27 suitable shape. Moreover, the convergence may be symmetrical or non-28 symmetrical, of uniform or non-uniform slope relative to the axislaxes and 29 continuous or non-continuous. Where a projection is formed from bar stock, e.g. square bar stock, all of the convergence may be in portions of 31 the edges closely adjacent the tip. ~tanges of exemplary included angles of 32 convergence between edges, e.g., throughout their length or only as the 33 edg~s approach the tip, include about 10 to about 35 degrees, preferably Pag~ 15 1 about 15 to about 30 degrees, more preferably about 17 to about 25 2 degrees, and stilt more preferably about 212 degrees. It is currently 3 considered optimumlbest for fracturing hard rock under heavy force to have 4 the edges converge at about 21-11411 degrees. One or both of the convergent edges n'1ay be chamfered, but these are preferably .not 6 chamfered.
7 As to the nature of the ti.p, it may ba a sharp point if desired, but this Is not 8 necessary. While the tip may be squared off, a rounded tip is preferred.
9 The tip may be cut as a segment of a circle with a radius of, e.g., about 0.1 14 to about 1 inch, preferably about 0.2 to about 0.7 inch, more preferably 11 about 0.2 to about 0.4 inch and most preferably about 0.3 inch.
12 For an excavating machine capable of exerting a given force, larger and 13 smaller tip'radii respectively, ail other factors remaining equal, r~suit in the 14 application of lass and more fracturing force per unit area to~rock strat2i.
Thus, in selecting tip radii when designing teeth according to the invention, i 5 persons skilled in the art may wish ~ta consider short radii for Less powerful 17 equipment and vice versa. While having a proper tip radius can be 18 ~ important when a tooth is first placed in service, it should be understand 9 9 that such radius is likely to change or~wear to a diffErent shape as the tooth wears.
21 , . - ' 22 The shape of ether edges and comers of~the projections may be varied 23 widely as desired, e.g., may be straight, curved andlor of other suitable z4 shapes.
Tooth length may also vary widely as appropriate for digging and for 2fi providing enaugh'avedap of projection and core to allow fonnatiort of welds 27 of the requisite strength between them. ~ ' 28 ~ While the number of projections may be at feast one~per tooth, preferably 29 two projections per tooth are preferred. There may be more than two projections per tooth. Where there are plural projections, it is pr~ferred that 31 there be divergence of one or more of these projections, for example 32 divergence of the outer surface of a projection from a central axis of th~

1 tooth or divergence of the outer surface ,of a projection from the outer 2 surface of another projection.
3 When divergence is present, for example, in at least one projection of a 4 tooth employed in trenching, moderate divergence assists the operator, ,when desired, in keeping the side of the trench vertical and in squaring off 6 an Intersection between a side and the bottom of the trench. Where 7 vertical side walls and squared-off side-wall to bottom-wall intersections are 8 not required or may be achieved in another way, at least one, e.g., all, of 9 plural projections) in a tooth maybe mounted with one or both of itsltheir major faces) parallel to or convergent with the tooth axis. Where there is 11 divergence, It may for example be about 1 to about 15, preferably about 6 12 to about 12, more preferably about 8 to about 10 and most preferably about 13 9, degrees from the tooth axis. Where the angle of divergence is .
14 expressed as the angle between major surfaces of two projections, the above r~naxima and minima of the above ranges are doubled. 'there c,~n be 1~ an advantage in limitirig the amount of divergence to no more than.~is 1 ~ needed to~ facilitate "squaring off";- in some tooth designs, ~ careful control 18 over the divergence angle will contribute to the strength of the tooth.
19 Providing divergence of orie or more projections from the core axis; when such is provided, can be facilitated by securing a projection to ~a core side 21 which, overall, is generally divergent from the core axis at the projection 22 angle of divergence. Alternatively, one may secure a projection to a "land"
23 representing a portion of the side of a core, the land being angled frann the 24 core central axis at the projection angle of divergence. Where a projection is not secured in the above manner, e.g., where the core has paraliel sides, 26 one or more shims may be placed between the inner surface of the 27 projection and the adjacent surface of the core to orient the projection at 28 the desired angle during fabrlcation,.e.g., during welding.
S9 In securing projections to cores, portions of projections may be secured in slots or grooves formed in cores or to longitudinal surfaces) of cores, 31 which is preferred, or in any other ~niay. A pair of projections is preferably 32 secured to opposite sides of a core; However, one may also secure a first 33 projection in a central groove at the front end of core, and secure eecond Page.17 1 and third projections to opposite sides of core. When at least one 2 projection is secured to at (east one longitudinal surface ~of~the core, which 3 is preferred, such projections) may and preferably do extend along at least 4 a portion of the at least one longitudinal surface and 'a portion of said at least one projection extends past the front end of the core with the tip and G at least a portion of the~converging edges projecting 'beyond the front end 7 of the core. . ' 8 Although other securing methods may be employed, welding is preferred.
9 One may $mploy any suitable welding techniques, which may include cleaning, e.g., by wire wheel or other means, and preheating the core i 1 andlor projection for any suitable time and temperature by any suitable 12 heating method under any suitable atmosphere, e.g., to 150-200 degrees 13 F. in air with a gas torch. One r~nay employ any suitable welding process, 14 flux, atmosphere, wirelrod type, temperature during'~welding, and any other details that might be considered useful. SMAW and GM~W are examples 16 of suitable welding methods. In gerierai, far welding excavator tooth 17 prosections to.cores, it is considered good practice to farm welds between 18 the parts everywhere possible. Among the post~welding operationslsteps 19 to be considered are cool-down processing (time, temperature, atmosph~re), quenching, wrapping the hot welded part in a welding blanket 21 to inhibit cracking of welds. Plate manufacturers' recommendations should 22 be considered.
23 A preferred welding procedure which has provided good results includes 24 cleaning the surfaces to be welded by wire wheel, locating th~
projection(s) properly located on the core arid tack welding them in place. The location 2'fi of the plates is then checked. Now, 3132" diameter TT5 flux-core wire is 27 applied to the joint where projection meets core. A preferred covey gas of 28 100% COz is used with the T-7~5 wire, it is best to apply multiple passes in 29 filling the joint. In addition, the temperature of the work-piece is held at 600 degrees lr. or less. After the welding operation, the finished part is 31 immediately wrapped in an insulating blanket for several hours to allow for 32 slow cooling to ambient temperature, thus avoiding formation of cracks in 33 the weld areas and heat affected zone of the weld.

1 Teeth according to the invention comprise part of a connector, called the 2 tooth connector portion, which is adapted to cooperate with another part of 3 a connector, called the excavator connector portion, located on an 4 excavator apparatus, as further described below, in this way, the tooth and .5 excavator apparatus may be connected to one another in working fi relationship. The tooth connector portion is located in or art the. core, 7 preferably at (in, on or near) the rear end of the core and more preferably in 8 or on the rearmost surface of the core. , However, the tooth connector 9 portion may be located in or 0n other surtaces of the core, e.g., its top l0 surface, where such exists, its bottom surface, where such exists, a lateral 11 surface(s~, where such exists, or the front surface, where such exists.
l 2 The tooth connector portion, includ~s at I~ast one concave or convex 9 3 connector surface, which .may have circular configuration, may have any 14 other suttat~le configuration and may be tapered or not tapered, but tapered 15 surfaces are preferred far most applications. ~ Viewed in transverse cross-16 section, the connector'surface~ may for example appear at least partly 1 T circular, oval, triangular, square, rectanguiar,~ diairond-shaped, polygonal, 18 of parallelogram shape, trapezoidal, a.modifcation of any of the foregoing ~19 or a composite shape (combinations of any of the above, e.g. generally 2~ square but with rounded corners).' The transverse cross-section iir~ay 21 appear uniform or var~iabie along most if not all of its length.
22 in longitudinal cross-section, the connector surface may be of any suitable 23 shape, whether uniform or variable along its length, including not tapered or 24 tapered, the latter being preferred.
26 The connector surface of the tooth oohnactor portion is positioned and 27 adapted to engage with and nondestructively disengage from at least one 28 mating surface of an excavator apparatus, 29 Locking members may be provided to seGUre teeth to excavator apparatus.
~0 For examples of different locking members, both metaAic, partly metallic 31 and non-metallic, see U.S. Patents C,Q47,487; 5,937,550; 5,638,621;
32 5,617,655; 5,579,594; 4,891,893; 5,853,048; 5,526,593; fi,079,132 and 33 6,247,255, which are incorporated herein by reference. it is not necessary 1 however that teeth according to the invention be held in fixed relation to 2 their adapters; for reciprocation of projections or teeth by air or hydraulic 3 drives, see tJ.S. Patent 5,485, fi85.
4 For purposes of the present invention,' an excavator apparatus is any excavating machine adapted to carry, in working position, one or more 6 teeth constructed according to the invention, .such as a mechanical or 7 hydraulic power shovel, backhoe,.trackhoe, .dragline or shaft drill. In 8 addition to such machines, excavator apparatus includes any digging g attachment or combination of attachments adapted to be mounted on an excavating machine and to carry, in working position, one or more teeth 11 constructed according to the invention, such as a blade, bucket, ripper arm, 12 cutting chain, dredge cutterhead, quick-toolrconnectldisconnect attachment 13 ~ or any suitable form of tooth adapter used with ariy of the foregoing.
14 Excavator apparatus usually comprises, as included; or attached elements, one or more excavator connector portions that have one or more concave 16 or convex surfaces adapted to mate,with and~form, in cooperation with one T'i' or more tooth connector portions of the core; at least a portion of a robust 18 connector for securing a tooth or teeth to the excavator apparatus with 19 sufficient strength to resist the loads imposed thereon in rock excavating ~ service. The mating surfaces) on the excavator connector portions and on 21 the tooth connector portions with which they .cooperate preferably represent 22 a nearly exact match, so that one fits snugly within the other in order to 23 minimize relative movement of the surfaces after itlthey lslare securely 24 seated against or within, one another. However, these surfaces need not in all circumstances be an exact matt for one another or be in interfacial 2fi contact over their entire confronting areas. They need only abut one 27 another over sufficient area to provide the required strength and load 28 resistance. ~. . ~ .
29 in preferred applications of the invention, a major surface of at least one projection is maintained approximately perpendicular to an axis of an 31 excavator apparatus. Approximately perpendicular means more nearly 32 perpendicular to than parallel to an axis, which may for example be the axis 33 of a pin or pivot, or an axis around which an ident~ied part such as a ripper 1 arm pivots, or may be an edge of a part such as a bucket or blade. if one 2 or more projections have~their major surfaces angled vertically andlor 3 horizontally (a.g., tilted andlor splayed) with respect to a plane that is 4 perpendicular to such an axis, such angles) will be selected to limit resultant tearing forces oh welds andlor other connections between the fi projections and their mountings (e.g., cores) as necessary to provide 7 commercially acceptable resistance to breakage of those connections and 8 of the projections themselves during operation, and morn preferably to 9 essentially prevent such breakage. Preferably, such angles) will be in the range of up to about 35 degrees, yet more preferably up to about 25 11 degrees, and most preferably up to about 15 d~grees, including zero 12 degrees. About 9 degrees is considered best. If the major surtaces are not 13 planar, e.g., are of curved, corrugated or other cross-section, the angle of 14 those surfaces relative to the axis may be judged on the basis of 'a sound approximation, for example, in the case of corrugation, the angle could 1 G possibly be measured in reference to a plane irvhich includes the peaks, of 17 the corrugations; or in the case of a curved,cross-sectlon, the ar~gie could 18 possibly be measured in reference to a plane which includes the edges of 19 the curved cross-section, Benefits can be realized from preferted embodiments of the invention 21 involving particular orientation of teeth relative to digging direction in 22 excavator apparatus. In these embodiments, the teeth comprise one or 23 more projections having a major surfacelsurfaces having a selected 24 orientation relative one or more planes that islets transverse to the excavator digging axis (e.g., the axis of rotation of sin excav$tor~2~rm 28 relative to the excavator boom). Preferably, one or mare projections isla~re 27 respectiv~ly in planes that are approximately perpendicular to the arm-28 boom axis. Still more preferably, each tooth comprises at least two 29 projections that~are in planes which diverge from one another.at progressively greater distances in the direction of their tips. Preferably 31 tooth connector portion and mating portion of the excavator apparatus are 32 sufficiently symmetrical to permit rotation of the tooth and projections 33 degrees, so that direction of digging by~~the projections can be reversed and 34 ~ the wear on the projections can ~be equalized. ~ ' 2 Figures 1-2 3 Figures 1 and 2 illustrate a particularly preferred embodiment'of an 4 excavator tooth according to the present invention, having a metallic core S with first and second projections~3.and 4. Were this core of circular 6 transverse cross-section, which is an optional embodiment of the invention, 7 the core could have a single, cylindrical, longitudinal surface. Mowever, in 8 the present figures, the core has four tangitudinal surfaces, including top 5, 9 bottom 6, first side 7 and opposite side 8. Its ends include front end 9 and rear end 10.
11 A connector portion 13~ is located at rear end 10 of the core and more 12 preferably in the rearmost surface of the core. Connector portion 13 13 includes a concave connector surface 14, which may be of circular or other 14 configuration, positioned and adapted to engage with and non-destructively disengage from at least one mating surface (not shown} of an excavator 18 apparatus (not shown}.
17 In the present disclosure and claims, wherever reference is t'nade to a 18 concave or convex connector 'surface, whether in or on a core, or in or on 19 an excavator apparatus, the singular farm of the word "surface" includes the plural of this term. For example, connector surface 14, corresponding 21 in shape with a truncated pyramid, comprises tsve surfaces, inciuding those 22 of.four convergent inner walls 1 S and of end wall 1 ~, 23 Core rear end 10 also includes rearwardly projecting ears 17 with apertures 24 18 in them to receive a locking pin (not shown}. These assist in fixing..the excavator tooth to any form of excavator apparatus, such as an adaptor 26 (not shown).
27 First projection 3 includes inner and outer major surfaces 20 and 21 while 28 . second projection 4 includes inner and outer major surtaces 22 and 23. In 29 this preferred embodiment, inner major surfaces 20 and 22 have an angle of divergence 24 between them.

1 Convergent cut ~dges 25 and 26 of each of these major surfaces, which 2 terminate in tip 27, define between them an angle of convergence 28. The 3 projection back edges 29 blend into edges 25 and 26 through short arcs 30.
4 Welds 31 join the back edges 29 and portions 33 of the projections to portions 32 of the core. Portions 34 of the projections, not welded to the G core, face one another and extend forward away from the core.
7 exemplary dimensions for the embodiment just described, which has been 8 found suitable for rock excavating service on power shovels, include an 9 overall length, from the backs of theears l7.ta the,tips 27 of projections 3 14 and 4 measuring 16 inches, a total projection length from back .edges 29 to 11 tips 27 of 9 inches, a convergence of projection cut edges 25 and 26 of 12 21.25 degrees, a radius for tips'27 of 0.3 inches, a radius of 0.5 inches for 13 arcs 30, a maximum vertical spread of the projection cut edges 25 and 26, 14 near their back edges 29 of 3.fi7 inches, a separation of the projection outer major surfaces 21 and 23 from one another, at their tips 27, of 10.75 ~16 inches, an angle of divergence of 18 degrees between the inner major 17 surfaces 20 and 22 of the,projections and a projection thickness of 1.25 18 inches where the projections have been cut from commercially available 19 Hardox 500 plate stock.
Figure 3 21 This figure illustrates an excavator to 38 having a me'tafiic core 39 of used 22 material, in this case a used cast tooth from which the remnants of the wom , 23 digging points have been ground away. There are also first and second 24 projections 40 and 41, similar to those of the preceding embodiment.
Core 39 comprises four longitudinal surfaces, including a top surface 42, a 26 bottom surface {not shown), a first side 43 and an opposite side (not 27 shown). This core also has front end 44 and rear end 45. Rear end 45 28 comprises tooth connector portion 48 including a concave connector 29 surtace at 46, similar to that of the preceding embodiment, as well as ears 5a and locking pin apertures 51.
. . Page 23 Figure 4 2 In this embodiment, excavator tooth 55 has a first projection 56, in the 3 foreground of the view, and a second projection 57 in the background.
4 While the inner major surface of first projection 5G is not shown, its outer major surface 58 is~ in the foreground of the view. A portion of the inner 6 major surface 59 of the second projection may be seen where a portion of 7 the first projection has been broken out in the view. The outer rna~jor 8 surface of the second projection is at the back of the part and thus it is not 9 shown in this view.
The inner major surfaces of the projections may be parallel, convergent or 11 pref~rably divergent, as viewed from above. Each projection has a lower 12 convergent edge fi0, upper convergent edge 61, tap 62 and back edge 63.
13 Unlike. the previous embodiments, the core and tooth connector portions of 14 the present embodiment are fabricated rather than cast. They include an upper inclined plate 67 and lower inclined piate 68 which are welded to and 16 extend laterally. between the inner major surfaces of projections 55 and 57.
17 Plates G7 and 68 are removed by a substantial distance' 6~9~frorn prbjection 18 tips 62. These two plates comprise convergent inner surfaces 70 and 71, 18 representing a concave or female connector surtace, e.g., pocket 72.
Apertures 73, po$itioned in plates 67 and 68 intermediate the projection 21 inner surfaces, are provided far insertion of a locking pin, as discussed 22 below. ~ ...
23 In this figure, an excavator apparatus is represented by a portion Qf an 24 adaptor 74, It may for exarriple be located on a digging Implement ar on any earth=working portion of an excavating machine. mere adaptor 74 26 includes a body 75 comprising a convex mating surface compatible with 27 pocket 72. Body 75 also includes a bore 77 which is in registry with 28 apertures 73 when the tooth is installed on excavator apparatus 74 and 29 held in place with the aid of locking pin 78.

Figures 5-6 2 While.former embodiments disclose fixing projections to outer surfaces of 3 cores, one can construct useful excavator teeth in which one or more 4 projections are mounted within one or more portions of a care. Figures 5 and 6 illustrate this.
B This ~mbodiment includes forked core 82 comprising main body 83 with T forwardly projecting first and second arms ~84 and 85, defining between 8 them a cavity 86. Here, a single projection 87 having cut edges 88, tip 89 9 and back edge 90, the latter being defined by two angled portions 91 and 92, is secured in cavity 86. Such securing is accomplished by welds 93 11 between the back 94 of the .cavity and the angled portions 91 'and 92 of 12 projection back edge.
13 Here, the~tooth connector port. ion is, for example, a male~member 99, 14 prei'erably of truncated pyramidal shape. It extends rearwardly from the end 100 of core main body $3. The mating surface is a female member, for 16 , exampte~ a cavity 101 in an excavator apparatus 102, shown in phantom 17 outline in figure 6.
18 A locking member, for example bolt 103, passes through matching hales 19 104 and 105 in tooth connector portion 99 and excavator apparatus 102.
By engaging the tooth and a portion of the excavator apparatus; this bolt 21 provides security for the connection between the tooth connector portion 22 and its mating surface in the excavator apparatus:
23 Figures 7-9 24 F,.xcavator teeth according to the invention can be used in virtually any kind of digging implement, for example above ripping arms Illustrated in figures 2fi ~ 7-9. In figure 7, an excavator tooth 107 having projections 108 is affixed to 27 a ripping arm 106 with the aid of locking, pin 109.
28 As shown in figure 8, a ripping arm, such as arm 106 of figure 7, may be 29 secured to a base plate 110, Webs 111 projecting from the rear of base 1 plate 110 may be squipped with mounting pins 112 to engage with a quick 2 connect-disconnect appliance, by means of which this digging implement 3 may be installed on an excavating machine, such as a power shovel or 4 backhoe.
trigure 9 includes a base plate 110, webs 111 and mounting pins 112, G similar to those of figure 8. However, here, two ripping arms 1136 are 7 ' secured to the base plate.
8 In figures 8 and 9, mounting pins 112 have axes 113. Major surfaces 114 9 of the projections 108 are approximately perpendicular to these axes.
f=igure 10 11 This figure illustrates another type of digging implement an which excavator 12 teeth of the present inventiori'rriay be used. Here, the digging implement is 13 a dredge cutter-head 117. It comprises central rotary shaft 118 having an 14 axes of rotation 119 which ~is perpendicular to the plane in which this view is drawn. Spiral vanes 120, extending from shaft 118 have inner ends 121 1 B and outer ends 122, support ring 123 being secured ~to the latter. A
plurality 17 of adapters 124 may be installed on ring 123 far mounting excavator teeth 18 . 125 with projections 12fi whose major surfaces 127 are approximately 19 perpendicular to axis 119.
Figures 11-12 21 Yet another type of digging implement in which the present invention is 22 useful is excavator buckets. As will be shown, such buckets may have '23 rectilinear or non-rectilinear cutting edges.
24 Bucket 131 of figure 11 includes sides 132, a back 133 and a bottom 134, having a substantially rectilinear cutting .edge' 135. Bdge 135 defines a 26 digging axis 136. Along this edge is distributed a series of adapters 137 on 27 which excavator teeth 138 according to the invention is mounted. Major 28 surtaces 139 of protrusions 140 in these teeth have their major surfaces 2g positioned approximately perpendicular to digging axis 13fi.

1 The bucket 143 in ftgure 12 compnses~ sides 144, a back 145 and a bottom 2 148, having across its front an at least parkly non-rectilinear cutting edge 3 147. Reference line 149, drawn through points at which the ends 148 of 4 edge 147 intersect with sides 144, represents the digging axis of the bucket. Adapters 150, distributed across cutting edge 147, are provided for 6 mounting a series of excavator teeth 951 on the bucket. To reduce clutter 7 in the drawing, the teeth have been omitted from fiwo of the five adapters.
8 Each excavator tooth includes projections 152 having major surfaces 153 9 that are approximately perpendicular to digging axis 149.
Figure 13 11 Teeth fabricated according to the present invention can be utilised in a wide 12 variety of excavating machines, one example of which is the rubber tired 13 backhoe machine illustrated schematically in figure 13. it includes body 14 157, and, at the front of the machine, a bucket 158, bucket arms 1 ~59 and bucket pivot 160. Rotational axis 161 of this bucket is perpendicular to the 16 plane in which the figure is drawn and therefore is represented by a dot at 17 the center of the pivot. A series of excavator teeth 162, only one being 18 shown in this view, is distributed across the front edge of the bucket, for 19 example in a manner similar to that showin in figure 11 or 12, These teeth have projections 183 with major surfaces 1fi4 approximately perpendicular 21 to axis 1 G1.
22 Towards the rear of the machine is a boom 1 g8 having a base pivot 169 23 upon which the boom may'~be raised,and lowered. Upper. pivot 170, having 24 . pivot axis 177, is a pivot point for excavator arm 171, which is.mounted at the upper end of the boom. At the lower end of the arm is an end pivot 172 26 on which a digging implement, for example pivoting rock ripping implement 27 173, is mounted. Hydraulic boom lift cylinder 174, arm pivoting cylinder 28 .175 and implement pivoting cylinder 176 are provided to raise and lower 29 the boom, and move the arm and ripping implement back and forth.
Excavator teeth according to the invention can also be used with backhoe 31 units equipped with means to allow the boom to swivel from side to sidd 32 around a vertical axis, but that feature has been omitted from the present 33 drawings to simplify them.

1 At the center of end pivot 172 is a pivoting axis 181 about which ripping 2 implement 173 pivots when digging through rocky strata. Excavator teeth 3 178, made according to the present invention, have projections 179. Their 4 major surfaces 180 are approximately perpendicular to axes 177 and 181.
Figure 14 fi Excavator teeth according to the invention have demonstrated their 7 durability in service on the buckets of large power shovels, such as that 8 shown schematically in figure 14. Typical machines of this type move on 9 crawler tracks 185 and include a body 186, boom 187, boom base pivot 188, boom lift cylinder 189, arm 190, boom-arm pivot 191, arm pivoting 11 cylinder 192, implement 193, in this case a rock ripping arm, implement 12 pivot 194 and implement pivoting cylinder 195. Pivots 188, 191 and 194 13 include, respectively, pivoting axis 200 about which the boom swings up 14 and down, pivating~ axis 201 about inrhich the arm swings in and out and pivoting axis 202 about which th~ implement swings back and forth.
16 Implement 193 is equipped with excavator teeth 203 according to the 17 invention. They include projections 204, the major surfaces 205 of which 18 are approximately perpendicular to axes 200, 201 and 202.
19 Figur~s' 15-16 Another example of many types of excavating machines on which the 21 excavator teeth of the present invention 'may be .used is draglines, an '~.
' 22 example of which is shown schematically in figures 15-1 t3. As is usual in 23 such equipment, this embodiment includes main boom 210 having base 24 pivot 211, overhead cable system 212 to suppork ~- and winch cable system 213 to draw - bucket 214, ail as shown in figure 15.
26 Base pivot 211 has a pivoting axis 215. As shown in greater detail in figure 27 1 G, bucket 214 has excavator teeth according to the present invention with 28 projections 217, These projections have major surfaces at least some and preferably all of which that era approximately perpendicular to axis 215:

1 The present disclosure has discussed and illustrated a number, but 2 certainly not ail, of the different ways in which the present invention may be 3 practiced: Accordingly, the following claims are intended to cover ail the 4 embodiments falling within their literal scope, whether specifically disclose herein or nat, and all equivalents thereof, fi D~FiNITI4NS
T Excavate, excavating, excavation, excavator, digging, ripping and related 8 terms employed herein are intended to be construed broadly to include all 9 forms of earth moving whether they result in formation of a cavity in the earth or not. For example, these tefms include not only trenching, dredging 11 and formation of other types of open cavities in the earth or in the earthen;
12 including rocky, sub-soil of a body of water, but also~ripping, scraping, 13 stripping, grading, leveling and other forms of earth moving that disturb 14 earth, as distinguished from rnerely carrying It from one place to another.
In this context, earth.includes not only soil, but also frozen soil, grave!
and 1 fi layers at or below the earth's surface comprising mostly mineral matter and 17 which may be essentially all .rock, and rt~ay include solid rock strata, which .
18. represents a particularly useful application of the invention.
'! 9 What is claimed is:

Claims (44)

1. An excavator tooth useful for fracturing rock strata, comprising:
A. a metallic core having front and rear ends and at least one longitudinal surface extending between said ends;
B. at least one projection formed from metallic stock and having a tip; said projection being secured to the core at least in part by welding with the tip and at least a portion of the length of the projection(s) extending beyond the front end of the core; and C. in or on the core, at least one tooth connector portion, including at least one concave or convex connector surface, of circular or other configuration, positioned and adapted to engage with and non-destructively disengage from at least one mating surface of an excavator apparatus.

2. An excavator tooth according to claim 1wherein the core is of circular cross-section and has a single longitudinal surface in the form of a cylinder.

3. An excavator tooth according to claim 1wherein the core is of non-circular cross-section and has plural longitudinal surfaces.

4. An excavator tooth according to claim 1 wherein the at least one projection preferably includes at least one cut edge.

5. An excavator tooth according to claim 1wherein the projection metallic stock thickness is about 1/2 to about 3, or about 3/4 to about 2 and 1/4 or about 1 to about 1 and 1/2, inches.

6. An excavator tooth according to claim 1wherein the tooth includes at least one projection which has on opposite sides thereof, as viewed in transverse cross-section, at least two approximately planar surfaces which are approximately parallel to one another.

7. An excavator tooth according to claim 1 having at least two of said projections thereon.

8. An excavator tooth according to claim 4 wherein two projections are secured to substantially opposite sides of the core.

9. An excavator tooth according to claim 4 wherein at least two of said projections have inner major surfaces, portions of which surfaces generally face one another and extend forwardly from the core, said portions, as they progress toward their tips, having an angle of divergence between them of about 0 to about 30 degrees, preferably about 2 to about 30 degrees, more preferably about 12 to about 24 degrees, still more preferably about 16 to about 20 degrees and most preferably about 18 degrees.

10. An excavator tooth according to claim 1wherein the metallic stock is of abrasion resistant steel having a surface BHN (Brinell Hardness Number) of at least about 225, preferably at least about 300, more preferably at least about 350, more preferably at least about 375 and still more preferably at least about 400.

11. An excavator tooth according to claim 7 which comprises iron, carbon, manganese and silicon, and optionally, but preferably at least one additional alloying element selected from the group consisting of chromium, nickel, boron, molybdenum, vanadium, titanium, copper, aluminum, niobium and nitrogen.

12. An excavator tooth according to claim 8 wherein the sulfur and phosphorous contents of the plate are respectively less than about 0.05, preferably less than about 0.04 and still more preferably less than about 0.030 percent by weight of the entire plate stock.

13. An excavator tooth according to claim 1 wherein there is a narrowing of at least one projection, between its generally longitudinal edges, in the direction of the tip.

14. An excavator tooth according to claim 1 wherein first and second longitudinal edges of at least one projection, or more preferably first and second edges of a plurality of projections, converge with one another, along at least a portion of their respective lengths, in the direction of their tip or tips.

15. An excavator tooth according to claim 14 wherein such narrowing, or such convergence, exists at least closely adjacent to the tip or tips.

16. An excavator tooth according to claim 14 wherein the projection edges converge, as the edges approach the tips, preferably at an angle of about 14 to about 35 degrees, more preferably about 15 to about 30 degrees, still more preferably about 17 to about 25 degrees and even more preferably about 21~2 degrees.

17. An excavator tooth according to claim 14 comprising convergence of at least portions of projection longitudinal edges along substantially straight lines, preferably closely adjacent to their tip or tips.

18. An excavator tooth according to claim 14 wherein convergence occurs over at least about 25% and more preferably up to at least about 100% of the length of the projection longitudinal edges

19. An excavator tooth according to claim 14 wherein the angles of convergence between edges as the edges approach the tips is generally about 10 to about 35 degrees, preferably about 15 to about 30 degrees, more preferably about 17 to about 25 degrees and still more preferably about 21~2 degrees.

20. An excavator tooth according to claim 1 or 19 including a projection with two convergent edges that are cut edges.

21. An excavator tooth according to claim 1 wherein at least one projection is secured to the core through at least one longitudinal surface of the core.

22. An excavator tooth according to claim 1, 7 or 21 wherein the projection or projections is/are secured to the core entirely by welds.

23. An excavator tooth according to claim 1 comprising a plurality of said projections that respectively extend along at least a portion of a given longitudinal surface and are secured to the core at least in part by welds between the given surface and adjacent portions of the projections.

24. An excavator tooth according to claim 1 wherein the tooth connector portion is located at the rear end of the core.

25. An excavator tooth according to claim 1 wherein the tooth connector portion is located in or on a rearmost surface of the core.

26. An excavator tooth according to claim 1 wherein the tooth connector portion is securely connected with a mating surface of an excavator apparatus.

27. An excavator tooth according to claim 26 wherein the tooth connector portion is a female member extending into the rear end of the core and the mating surface is a male member on an excavator apparatus.

28. An excavator tooth according to claim 26 wherein the tooth connector portion is a male member extending rearwardly from the rear end of the core and the mating surface is a female member on an excavator apparatus.

29. An excavator tooth according to claim 26 wherein a locking member engaging the tooth and a portion of the excavator apparatus provides security for the connection between the tooth connector portion and the mating surface.

30. An excavator tooth according to claim 29 wherein the locking member is a resilient insert or metallic pin.

31. An excavator tooth according to claim 26 wherein the excavator apparatus is an excavating machine adapted to carry, in working position, one or more teeth constructed according to the invention.

32. An excavator tooth according to claim 26 wherein the excavator apparatus is an excavating machine selected from the group consisting of power shovels, backhoes, draglines, dredges, graders and bulldozers.

33. An excavator tooth according to claim 26 wherein the excavator apparatus is a digging attachment or combination of attachments adapted to be mounted on an excavating machine and to carry, in working position, one or more of said teeth.

34. An excavator tooth according to claim 1 connected with a bucket having a mounting pin for connecting the bucket to an excavating machine, the tooth having a projection with a major surface which is head in approximately perpendicular relationship with the longitudinal axis of the mounting pin.

35. An excavator tooth according to claim 1 connected with a rock ripping tool having a mounting pin for connecting the tool to an excavating machine, the tooth having a projection with a major surface which is held in approximately perpendicular relationship with the longitudinal axis of the mounting pin.

36. An excavator tooth according to claim 1 connected with a bucket or blade at a substantially rectilinear cutting edge of the bucket or blade, said edge defining a digging axis, a major surface of the tooth being held in approximately perpendicular relationship with that axis.

37. An excavator tooth according to claim 1 connected with a bucket or blade having an at least partly non-rectilinear cutting edge having ends at sides of the bucket or blade, said bucket or blade having a digging axis defined by an imaginary line connecting said ends, a major surface of the tooth being held in approximately perpendicular relationship with that axis.

38. An excavator tooth according to claim 1 connected with a digging end of a pivotable ripping arm for an excavating machine, said arm having a pivoting axis about which the arm swings in operation, a major surface of the tooth being held in approximately perpendicular relationship with the axis.

39. A method of excavation with an excavating machine having an arm with a pivot affording angular movement of an end of the arm about a central axis of the pivot, said arm supporting and delivering digging force and motion to a digging implement having projections, said method comprising applying such force through projections that are formed of cut plate stock and have major surfaces that are approximately perpendicular to said axis.

40. A method of fracturing rock or frozen earth with an excavating machine having an arm with a pivot affording angular movement of an end of the arm about a central axis of the pivot, said arm supporting and delivering digging force and motion to a digging implement able to apply sufficient force through the tips of projections on said implement to break up the strata, said method comprising applying such force though projections that are formed of cut plate stock and have major surfaces that are approximately perpendicular to said axis.

41. A method according to claim 39 or 40 comprising applying such force through one or more teeth having edges that converge at angles of convergence between edges as the edges approach the tips of generally about 10 to about 35 degrees, preferably about 15 to about 30 degrees, more preferably about 17 to about 25 degrees and still more preferably about 21~2 degrees.

42. A method according to claim 39 or 40 comprising applying such force through one or more teeth respectively having at least two of said projections with tips and inner major surfaces, portions of which surfaces generally face one another and extend forwardly from the core, said portions, as they progress toward their tips, having an angle of divergence between them of about 0 to about 30 degrees, about 2 to about 30 degrees, or about 12 to about 24 degrees, or about 16 to about 20 degrees or about 18 degrees.

43. A method according to claim 39 or 40 comprising applying such force through teeth wherein the plate stock is abrasion resistant steel plate having a surface BHN (Brinell Hardness Number) of at least about 225, more preferably at least about 300, more preferably at least about 350, more preferably at least about 375 and more preferably at least about 400.

44. A method according to claim 39 or 40 comprising applying such force through teeth which comprise iron, carbon, manganese and silicon, and optionally but preferably at least one additional alloying element selected from the group consisting of chromium, nickel, boron, molybdenum, vanadium, titanium, copper, aluminum, niobium and nitrogen.