US2952085A

US2952085A - Reversible tooth for earth digging equipment

Info

Publication number: US2952085A
Application number: US682720A
Authority: US
Inventors: Gerald A M Petersen
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-09-09
Filing date: 1957-09-09
Publication date: 1960-09-13
Anticipated expiration: 1977-09-13

Description

Sept. 13, 1960 G. A. M. PETERSEN 2,952,035

REVERSIBLE TOOTH FOR EARTH DIGGING EQUIPMENT Filed Sept. 9, 1957 3 Sheets-Sheet l INVENTOR.

3/ Gerald A. Petersen Sept. 13, 1960 a. A. M. PETERSEN 2,952,085

REVERSIBLE TOOTH FOR EARTH DIGGING EQUIPMENT Filed Sept. 9, 19s? 3 Sheets-Sheet 2 INVENTOR. 663410 ,4. PfIZ'AiSZ-W BY K/Z Q p 1950 5. A. M. PETERSEN REVERSIBLE. TOOTH FOR EARTH DIGGING EQUIPMENT Filed Sept. 9, 1957 3 Sheets-Sheet 3 INVENTOR. GERAlD 14.??5!

Imam? Patented Sept. 13, 1960 REVERSIBLE TOOTH F OR EARTH DIGGING EQUIPMENT Gerald A. M. Petersen, P.O. Box 330A, Santa Clara, Calif.

Filed Sept. 9, 1957, Ser. No. 682,720

The terminal portion of the term of the patent subsequent to Mar. 17, 1976, has been disclaimed 13 Claims. (Cl. 37-142) This invention relates to a new and improved reversible tooth for earth-digging equipment, such as earth angers and the like. At the present time earth-digging equipment of various types employs a plurality of digging teeth which absorb much of the wear encountered by the tool and also are the portion of the equipment most likely to be broken. The present invention relates to a replaceable tooth for earth-digging equipment which is conveniently and rapidly replaceable and which further may be reversed so that when the tooth is worn on one side, it may be turned over and used on the other side.

This application comprises a continuation-in-part of my co-pending United States patent application Serial No.

620,291, filed November 5, 1956, now Patent No. 2,877,- 574, for Reversible Tooth for Earth-Digging Equipment. Accordingly, one of the principal objects and advantages of the present invention is the provision of a tooth which may be attached to and removed from a shank plate or other portion of an earth-digging tool or other piece of similar equipment with a minimum of time and effort.

Another object and advantage of the invention is the provision of a reversible tooth which may be used first on one side and, when worn, may be turned over and used on the other side. One of the particular features of the invention is the facility with which the tooth may be reversed and, after having been reversed, securely locked in position with a minimum of labor and without the use of special tools or equipment.

Still another feature of the invention is the provision of cooperating means on the tooth and shank plate or other portion of the equipment to which the tooth is attached, which assist in securing the tooth in place.

A still further feature of the invention is the provision of cooperating means on the tooth and shank plate to which it is attached, which prevent the tooth from being displaced from its proper position when the tooth is subjected to severe stress, such as striking a hard object at one corner of the tooth.

One of the principal advantages of the instant invention is the fact that wear of the tooth occurs on its edge. In other forged replaceable teeth, the means of connection employs a stud and a socket. Wear occurs in the zone of connection between the stud and socket, which is particularly subject to abrasion and other frictional deterioration. Since the socket is conventionally a permanent part of the earth-digging equipment, deterioration of this part of the connection causes discard of the equipment, thereby defeating a primary reason for the use of replaceable teeth. The instant invention eliminates the socket principle and the tooth is wide enough to protect the underlying shank from wear; hence the shank is truly permanent and need not be replaced despite wearing out of many replaceable teeth.

Another object of the invention is to provide means whereby a tooth is formed having a slot extending forwardly of the proximal end thereof, which divides the tooth into two discrete portions at the proximal end. A

shank is provided having a step or recess shaped to receive at least a portion of the proximal end of the tooth and, further, having means extending through the slot and engaging the edges of the slot to hold the tooth in position in the shank. Further, the tooth and shank may be provided with cooperating means in the form of mating depressions and protuberances or other means hereinafter described in greater detail, which cooperate to prevent withdrawal of the tooth from the shank prior to the time when it is desired to reverse or replace the tooth.

An important feature of the present invention is the fact that the tooth is held in a shank and the shank is secured to the major piece of equipment, such as an auger, so that the tooth and even the shank may be replaced when worn or damaged, without the necessity of discarding the major piece of equipment.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

Fig. l is a perspective view of a portion of a piece of earth-digging equipment,- such as an earth anger, with a plurality of teeth constructed in accordance with this invention attached thereto;

Fig. 2 is an enlarged sectional view taken substantially along the line -2-2 of Fig. 1;

Fig. 3 is an enlarged top plan view of a tooth and a portion of the adjacent shank;

Fig. 4 is a sectional view taken substantially along the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 2 of a modified tooth;

Fig. 6 is a top plan of the structure of Fig. 5 with the bolt head removed;

Fig. 7 is a fragmentary view of a modified structure similar to that shown in Fig. 5;

Fig. 8 is a view similar to Fig. 2 of a modified tooth;

Fig. 9 is a side elevation of the tooth shown in Fig. 8;

Fig. 10 is a top plan thereof;

Fig. ll is a view similar to Fig. 2 of a further modified tooth construction;

Fig.12 is a top plan of the tooth shown in Fig. 11.

The present invention relates to a reversible replaceable tooth 11. As shown in Fig. l of the accompanying drawings, a plurality of such teeth may be attached to a piece of earth-digging equipment, such as an earth auger 12 of the type used to dig holes for utility poles. Reference is made to United States Patent No. 2,578,014 which illustrates an earth auger to which the present invention may be attached. As an integral part, or, as shown in the accompanying drawings, a separate part of such equipment, there is provided a shank p1ate'13 attached to the main portion of auger 12 by means of bolts 14. The shape of shank plate 13 varies considerably and the number of teeth 11 attached thereto is likewise the subject of variation. As illustrated in Fig. 1, one such shank plate 13 provides a means of attachment for three teeth 11, the attachment means for each tooth being substantially identical. Accordingly, the attachment of a single tooth to the shank plate will be described.

Shank plate 13 is formed with a plurality of outwardly projecting roots 16 corresponding in number to the teeth and disposed in a direction and at an angle to the axis of rotation of the tool which is determined by proper engineering design. The width of root 16 is substantially the same as the width of tooth 11 and the length of the root is sufiicient to form a secure attachment. Each root 16 is cut away in a step having a back wall 17 substantially perpendicular to the direction of the tooth and a bottom wall 18 substantially parallel to the direction of f j Projecting upward from bottom' wallilifare three pro? J Ituberanceslhil;122; (The two prothherances 2.1 am; located inwardlyof' the central *axisof aperturet19 and to either side thereof, and the third protuberance 22 located midway ofthesides oi therootand; forwardly jofaperturekl9. 1 'flProtuberances21,122 are of a shape" Y andhave'afunction ashereinafterdescribed. 'f

absorb wear andlgwithstand shook. {)Toothll 'is of bstahtia lly the same width? throughong havingparallel side" edges26 atleastat its proximalendg The distal faces;

,2'7pf1thetooth taperlat an angletof approximately 6 I hreplacedbr:resharpenedp; [The proximal .of the to'othhas {substantially parallel top andbottom faces 31 and-32- and j rearendwah 33 perpe'ndi'cnlar'to faces '31'andi32 and r forwardly from ,rear end; wall 331 of the toothandthe lengthf of slot 34 is'fsuchthaLiwhen a earriagetboltfiti isl i inserted 111 the 'slot 34 and through aperture .19 tooth ,11 is properlylocated in,position. j j f "Bothathe top and bottom. proximal faces 31; and 320i ")6 y .thetooth' are formed -w'ith three"depressionsfily ll, 42 corresponding'in positionto the threeprotnherancesczl, 1 .21, 22 on shank plate13. Asshownhr Fig. l4and' con- Tsidering the depression 541 111; the top proximal face 31, each of the rearward disposed depressions 41' 'extend's'i 26.?The forward wall 43 of depression 41*slo' msv down;

' wardly-re'arwardly at an angle ofg'approxirnately 153 commencing' along ajline displaced rearwardly I returns 44 of bolt .36ashort distance. '-Tharea 1i.4ei

of the depression slants downwardlyforwardlyatan angle 545,? and intersects,foiwardwall43toptOide a max mum depth or the depression as --indicated by referenc I numeral 47) approximately one quarter the thickness of .thGtOOth. Z V

I approximately one-quarter the thickness of theitooth;

, mate'lyf 45j 4,, or

i has been stated, positioned andfsh'aped to fit snugly with b protuberance s ZIon either side areforrned extendin iii-n 1 'wardly from side edges 26 a distanee equal tto thevviclth .faee'figl--ofprotuberance21 is disposed at an angle of with respect to hottom wall l3,uand front face 52 slants downwardly-forwardly at an angle of substantially I in seating of the tooth.

The width of slot 341s equal to the Width of s uare neck the V'tooth .The, root, is termed an 7 aperture 19 extending through bottornjwall' 18'hdiacent' the outerend of the iroot 'and centrally locatedrelativetothe sides-f thereof;

Tooth 11 formed ofahardpieceof metalsoasto and aretmncated tofonn a forward end 28, therehy providing affirst.andyasecondseuttingedge 29 on, oppo site .faces of *thegtooth; ,,Oneof the advantages of the' present invention is the fact that the; tooth: may be used with one face upward and then reversed so that twice the'wear may be obtainedjbefore; the tooth, need? be I 2' sideedges 26. .Back end wallf33of the] tooth seatsagainst I back Wall 17 of the step. rectangnlarfslot '34hextends F acrosswthe width. of'the toothfrom fslot'34 to side edge? tromthe'eena. 1'

Forward depressionf42-hasa" width slightly greater than one-quarter the widthof tooth 1'1 and has a depth i Forward depression 42 1s centrally disposed with respect to side edges '26 of the tooth andextends forwardly of forward wall'48 Of SlOt34 substantially horizontally a distance;substantially-equal to the widthof" depression f .425; The forward wall ,49 of depression 42 (as; Shown in'Fig. '2 and considering the depression! 42; in top' fajceq Y 31) I slopes upwardly-forwardly at an angle (of approxb; J

; Protuber a ces 2 1,f21," 22 3011 1 shank plate, 13 aregasil q I i in depressions 41; 41; 42. :Accordinglythe rearward between slot 34 and edge 26 oftoothf11. The rearward f 15; Forwarduprotnberan'cen has a widthequal'to the) widthof forward depression 42 ontooth Hand a height equalfto" the depth thereof extending forwardly -from' aperture 19, and its corner edges are chamfered to assist.

Tooth 11 may befattaohedtoshankplatefBby a earr'iagebolt" 36 having "a square nec k ifi' under its head 57.

"feature of the invention materially s "the'tooth'orareplacing the same;

rornfbottom 1810f the'stepoflshank 16a; in a'position,

ence numeraI GSQ The pnr'poseof the" depression 65 is i fappliedgtofthe faces to'eitherside of slot 34 to seat I projections 21in grooves 41. It'willfur'therfbeseen that rather than b'eing of the same width.

t heinvention- Reference line fifi shows a representativew.

'ZOdigging 67 shows how, even with considerable wear of the "distal ofthetooth, useful life thereof is maintained before the tooth needbe replaced.

torthatof Figs. 5' and 6 except for the fact'that only one 7 5 5 6 nnderhead harnesses and hence two sides ofthex square neck engage the side edgesof slot,34' and v A i f a third side of; the neck seatsagainsttfiront wall48, of Y slot 34." WhennutSSlstightened on boltfifi, fhead57.

' hearsagainsttop face, 31 oftooth 11 and locks ltheftooth snilglytoshank pla teli'a. The locking of the tooth to the shank 5 plate is accomplished by' the "cooperationof the parts as heretofore. described. Thus back face-33 f'toQth-IILe gagegbaek wall, '17 OfSilfiIlkPlhillgLiand. f bottom facqliz'ofthe tooth engagesbottom walll lfi of j 1 shank plate 13. In addition;

protuberances

21, 21;;221, Q fit into depressions 41, .41, 42 and additionally neck; 56] 1 1 of boltf36 engages the side and. frontwalls'of'slot 34.

In{ the event that toothll strikes a hardobjeet on one corner, protuherancesll, 21,12; assist in preventing the p I tooth'from' 'being knocked out of alignment; inasmuch as they -resist any twisting rnovernentrofthe tooth.

It will be. seen. that, in order to remove a'tooth 11," v

it is not. necessary to remove nut 58 completely from T58 is loosened sufficiently sothat protuberances 21,121, 22 r cleardepressioiis 41, .41, ,42; whereupon the tooth may e headrawn forwardly by reason, of the fact that; there is" bolt 36 r to removeholt 36, from aperture 19. T Nut provided trslotl 34 insteadof'merely ya holt'hole. This plifies reversing V v Afterthe' tooth has been used nntil one cutting edge 29,,is' worn; the tooth is reversed; as has been indicated,

",iandfltheflother edge,-29 used. When the tooth must he s i replaeedor resharpened, the construction heretofore de- I 'scribedexpeditestheseoperations. l

'c111sive,{ar'e similarin many respects to that form'showmf in Figs. 1-4,.inclusiveyand accordingly, for purpose of and shank is'ao'mitted; correspondifig partsof the tooth 1 h eing given the same referenoe numerals in "the acc'om-;.

i l g drawi In Odifioation ,40

sions" 42 are eliminated. A protuberance 61 is formed extending'upinto; sloti34i'n a position ahead of neck:

hehindiholt head 56 and forwardly-"of rear wall 17. .Pro. t I it 'j'ections 61; and 62 stabilize the tooth relative'to theshank i platehy preventing relative movement in any direction transverse to the axis of the bolt 3.6. It will be.understood that the width of projection 61' is substantially 1 equal to the width of the slot 34, but, as illustrated in.

the forward wan of the slot.- .Itwill further'be observedfi 5 hatforwardly of1slot'34; boththe top andbottom surfaces of the tooth are depressed, as indicated by refer to insure that, when nut 58 is drawn tight, the pressure. e

the outer end of the shank is turned up; as indicated port, shank. roots 1611 i are rnade wider than thetooth, Fig. 5 illustrates oneof the features and advantages of.

line of diggingwhen the tooth is new; whereas line of."

The modification of Fig: 7' is inmany projectionfirextends upfront the lfibso thatthei;

3 space behind neck 56 of bolt 36 isclear, in the same manner as is shown in Fig. 2.

Figs. 8-10, inclusive, are similar to the modification shown in Figs. 5 and 6, except that the shape of tooth 81 differs. It will be understood that the shape of the tooth is subject to considerable variation. The tooth shown in Fig. 8 is designed for trenching machines, The distal corners 82 are beveled in top plan, and beveled facets 83 are formed at the corners, as best indicated Fig. 10. It will be understood that other shapes of teeth may be employed in all of the modifications of the invention. This manner of fastening tooth 81 to its shank is essentially the same as in Figs. 5 and 6. v

Figs. 11 and 12 illustrate a further modification of the invention. The proximal top and bottom faces 87 of tooth 86 are roughened or knurled and similarly the bottom face 88 of the step of the shank is knurled or roughened. It will be understood, further, that only one of the two

surfaces

87 or 88 need be roughened, particularly when the tooth is not subject to as severe stresses as the teeth of the previous modifications are capable of absorbing. When the nut 58 is drawn tight on carriage bolt 36, the roughened surfaces grip against each other and prevent dislodgment of the tooth. It will be understood that a slot 89 is formed extending forwardly from the proximal end of tooth 86 and that this slot cooperates with square neck 56 of carriage bolt 36 to hold the tooth against displacement. The roughened surfaces 87 and 88 function in much the same manner as the projections 21, 22 and

depressions

41, 42.

-What is claimed is:

1. A tooth for an earth-digging tool comprising a unitary, hard piece of material having a tapered distal portion and a proximal portion formed with substantially parallel proximal external faces, said proximal portion being formed with a substantially rectangular slot extending forwardly from the proximal end of said tooth for the reception of fastening means in a direction transverse to said proximal external faces to form a pair of rectangular prongs, each of said proximal external faces being formed with a plurality of V-shaped depressions extending transversely across the width of at least one external surface of said prong, a first of said depressions being located rearwardly of the inner terminus of said slot and to one side thereof, and a second of said depressions being located rearwardly of the inner terminus of said slot and to the side thereof opposite to said first depression.

2. A reversible tooth for an earth-digging tool comprising a unitary, hard piece of material having an outwardly tapered distal portion truncated to provide a first and a second cutting edge disposed on opposite faces of said tooth, and a proximal portion formed with substantially parallel proximal external faces, said proximal portion being formed with a rectangular slot extending inwardly from the proximal end of said tooth to form a pair of rectangular prongs, the edges of said slot being substantially parallel to the side edges of said tooth, each of the top and bottom faces being formed with a V-shaped depression extending transversely across the width of said prong, a first of said depressions being located rearwardly of the inner terminus of said slot and to one side thereof, and a second of said depressions being located rearwardly of the inner terminus of said slot and to the side thereof opposite to said first depression.

3. A reversible tooth for an earth-digging tool comprising a unitary, hard piece of material having an outwardly tapered distal portion truncated to provide a first and a second cutting edge disposed on opposite faces of said tooth, and a proximal portion formed with substantially parallel proximal external faces, said proximal portion being formed with a substantially rectangular, vertical slot extending inwardly from the proximal end of said tooth to forma pair of rect'angular prongs, the edges of said slot being substantially parallel to the side edges of said tooth, each of the top and bottom faces of said prongs being formed with a depression extending transversely across the width of said prong, a first of said depressions being located rearwardly of the inner terminus of said slot and to one side thereof, a second of said depressions being located rearwardly of the inner terminus of said slot and to the side thereof opposite to said first depression, each of said first and second depressions being shaped with a rearward wall disposed extending forwardly inwardly at an angle of approximately 45 and a forward wall intersecting said rearward wall extending rearwardly inwardly at an angle of approximately 15.

4. In combination in an earth-digging tool, a shank formed with at least one step therein having a rear wall anda substantially transverse bottom wall, said shank being apertured in said bottom wall, a plurality of protuberances on said bottom wall, a tooth formed of a unitary piece of material, the proximal of said tooth fitting into said step and abutting said rear and bottom walls thereof, said tooth having a tapered distal portion and a proximal portion formed with substantially parallel proximal external faces, said proximal portion being formed with an aperture for the reception of fastening means in a direction transverse to said proximal external faces, at least one of said proximal external faces being formed with a plurality of depressions, a first of said depressions being located rearwardly of the inner terminus of said aperture and to one side thereof, and a second of said depressions being located rearwardly of the inner terminus of said aperture and to the side thereof opposite to said first depression, said protuberances fitting into said depressions, fastening means passing through the aperture in the bottom wall of said step and through the aperture in said tooth and cooperating with said protuberances and depressions to secure said tooth to said shank against forces tending to twist said tooth relative to said shank, and a projection on said shank extending up into the forward portion of said slot ahead of said fastening means.

5. In combination in an earth-digging tool, a shank formed with at least one step therein having a rear wall and a substantially transverse bottom wall, said shank being apertured in said bottom wall, a plurality of protuberances on said bottom wall, a tooth formed of a unitary piece of material, the proximal of said tooth fitting into said step and abutting said rear and bottom walls thereof, said tooth having an outwardly tapered distal portion and a proximal portion formed with substantially parallel proximal external faces, said proximal portion being formed with a slot extending inwardly from the proximal end of said tooth, the edges of said slot being substantially parallel to the side edges of said tooth to define a pair of prongs, each of the top and bottom faces of said prongs being formed with a depression extending transversely across the width of at least one external surface of said prong, a first of said depressions being located rearwardly of the inner terminus of said slot and to one side thereof, and a second of said depressions being located rearwardly of the inner terminus of said slot and to the side thereof opposite to said first depression, said protuberances fitting into said depressions, and fastening means passing through the aperture in the bottom wall of said step and through the slot in said tooth and cooperating with said protuberances and depressions to secure said tooth to said shank against forces tending to twist said tooth relative to said shank.

6. In combination in an earth-digging tool, a shank formed with at least one step therein having a rear wall and a substantially transverse bottom wall, said shank being apertured in said bottom wall, a plurality of protuberances on said bottom wall, a tooth formed of a unitary piece of material, the proximal of said tooth fitting into said step and abutting said rear and bottom walls thereof, said tooth having an outwardly tapered distal portion and a proximal portion formed with substantially parallel proximal external faces, said proximal portion being formed with a vertieal substantially rectangular slot: ex r tending inwardly iromfthe proximal end 'of said tooth to formalpair. of rectangular prongsrthe edges of said slot;

formed with a depression extendingtransversely' across,

I asserts the width of said prong, a first ofsaid depressionsbeing tersecting said I rearward wall extending rearwardly' 111-,

I located, rearward1y1 of'the inner-terminus of said slot and to one side, thereof, and a second of said depressions I being located rearwardly of the inner terminus ofsaid slot 5 and to the side thereof opposite tosaid first depressionr, 1 each of said, first and second depressions being shaped with a rearward -wall disposed extending forwardly inwardly at an angle of approximately 45 and, a forward wall infprises asecond protuberance extending up into said slot,

I behind said fastening means. f by I J i I 12; "In combination, in an earth-dig fag tool a unitary 15 wardly at an angle of approximately 15, saidprotuber- 'ances fitting into said depressions, and fastening means passing through the aperture in the bottom wall of said step and through the slotlin saidtooth andloooperating s with said protuberances anddepressions to-secure said tooth to said shank against forces tending to twist, said 1 tooth relative to saidshank.

7. In; combination in an earth-diggingtool, a shanlc formed: with at least one step therein having a rear wall r g and" a substantially transverse bottom wall, said shank beingapertured insaid bottom wall, a pluralityof promberances on said bottom wall; atooth vformed of a unitary f .piece ofrnaterial, theproximal of Said tooth fitting intosaid step and abuttings-aidiear and bottom walls tamer,

said tooth having a distal portion tapering outwardly and a proximal portion formed with substantiallytparallelprox imal faces, said proximal portion being formed with a slot.

extending inwardlyfromthe proximal, end of said tooth,

the edgesof said slot being substantially parallel to the side edges of said tooth, each ofsaid proximal faces being formed with" aplurality of depressions, :a first ofysaid depressions being locatedtrearwardly of the inner terminus of said slotand to onelside thereof, and a second of said I depressions being located rearwardly of the inner terminus of said slot and to the side thereof Qppositeto said first depression, said protuberances fitting into said depressions, p

and a carri age bolthavingasquare neckpassiug through t the aperture in the bottom wall of said step and through 1 theslot' in said tooth, said slot being dimensioned whereby" two sides of said neck of said bolt abut ,thesides of said slot and athird side of said neck abuts the inner, end of said slot, said I bolt cooperating with said protuberances' and depressions to secure said 'tooth'to' said shankagainst forces tending to twist saidtooth relative to said shank.

8. In combination, in'anrearth-diggingtooh axuriitary i 1s. Thecornbination of claim 12, which and cam-j prises side depressions on said tooth on either side of said,

[R slot and'side protuberances. on said shank positioned to shank shaped to receive theprox-imal end of atooth, a;

tooth formed of a unitary piece of material and having i n proximal cndshaped to fit said shank, said tooth having,

top and bottom forwardlyconverging tapered distaltaces, i V

and a substantially rectangular proximal portion rearward 1 of said distal faces having substantially parallel top and bottom external surfaces and "a longitudinallyforwardly r extending, substantially rectangular slotj extending for-,1 wardly from the proximal end 0f saidfltooth extending through from said top to'said bottomsurface and dividing said proxir'nal end into two discrete prongs: each substan' tial ly rectangular in shape, atleashone surface of: each i said prong being formed with a shallow depression ex-a tending transversely across said prong, and}means Carried by said' shank to restrain dislodgernent of "said tooth from said shank, saidlmeans engaging said depressions, said prongs being imperforate and no portion of said means extendinginside said prongs.

Q9 The combinatiortof claimsin which as means extends through said slot detachably holdingsaid tooth and shank in engagement with each other and inwhich said means comprises-1 cooperating meanson 'saidtoothi and shank to restrain dislodgement of said tooth from 'saidshank. I M r I when said fastening means-is inoperative.

ll. Thecombination of claim 10 whichturtheneomfl shank, shaped to receive the'proximal end of a tooth, a

I tooth formed of a unitary piece of, material and, having I its proximal end shaped to fitsaid shank, said tooth hav r topand bottomforwardly converging tapered distal I aces,;and a substantiallyrectangular proximal portion A rearward 0i said distal faces having substantially para-lleli s top and bottomsexternal surfacesanda longitudinally forwardly {extending substantially rectangular slotextenda ingtrorn the proximal end ofisaid tooth extending through from saidt op to said bottom 'surfaceancl dividing Saidff': proximal end-into two discrete prongs eachlsubstantially 1 rectangular inwshape, and me'anscarried by said shank p to, restrain dislodgmentrofi said tooth from said s hank', c

said {means engagingsjaid prongs, said prongs being imperforate andno,portionofzsaid means extending, inside c said prongs, said: means extending through saidslot de- :tacl ablyholding said tooth and shank in engagement with,

each otherand in'which 'saidmeans comprises cooperat tag means on ,said to'othqand shank to restrain dislodg-; j ment ,of said tooth fromsaid shank; said shank being f fformedwithastep shaped to receive a part or the proxy a ,irnal; end of saidl tooth and the portion of said shank formed with said, step is also formed'witli an apertureoy I ,and said last-mentioned means comprises fastening means f extending through said slot and aperture in said shank todraw said tooth toward said shank to engage said co ioperatingmeanswhen said fastening means is operative ,a'nd'to permit disengagement of said cooperating means I ,when-s'aidtastening means is inoperative, said slot 'exn tendingsubstantially. forwardof said aperture, and a first protuberance on said shank extendingup into said slot 4 =between saidfastening meansand the forward end of- *saidslot;

fitfinto said sidedepressionsg t ReferencesCi'ted in the'file of thispatent I, i V

UNITED STATES PATENTS Long "in; Sept; 3, 1878' a Gasman can; 1911: I