US2603009A

US2603009A - Dipper tooth construction

Info

Publication number: US2603009A
Application number: US5913A
Authority: US
Inventors: Forrest E Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-02-03
Filing date: 1948-02-03
Publication date: 1952-07-15
Anticipated expiration: 1969-07-15

Description

July 15, 195 F. E. SMITH DIPPER TOOTH CONSTRUCTION 2 sriEEws -snEETll Filed Feb. 5. 1948 Inventor Forrest Smith y 15, 1952 F. SMITH 2,603,009

DIPPER TOOTH CONSTRUCTION Filed Feb. 5, 1948 v 2 SHEETS-SHEET 2 H I h Inventor 1| fbr'rest E Smith Patented July 15, 1952 Yumrso STAT OFFICE 2,603,009 nrrrnn roorn oonsrnno'rion Forrest E. Smith, Signal Mountain, Tenn.

Application February s, 1948, Serial No. 5,913

'7 Claims. (01. 37--142) the earth or material being excavated or loaded.

It is desirable that these teeth have sharp cutting edges to facilitate forcing them into the material beingdllg or loaded. It has been established that sharp teeth not only require less force but enable the digging time per ton to be substantially reduced with decreased wear and tear on the excavator. Unfortunately, in digging in rocky soil orin excavating certain types of ores, the teeth become blunted very quickly andmust be frequently replaced. While it ispossible to send the teeth to the shop to have the lost metal replaced bywelding and the point-reshaped, such practice is not only expensive but requires that each bucket h ve se r s t s e te i V 7 The most common commercial form of renewable teeth require special pins, keys, bolts or the like for fastening purposes. v In most cases these are damaged or worn in'a manner preventing easyremoval and nearly every time a point is changed a new fastening pin or bolt is required for proper fit. Removal of the old tip'and installation of the new has been diflicult and time consumingparticularly under field conditions. Further, the holes for such fastening members cause serious weakening of the tooth base. In order to provide adequate strength it has been necessary for the fasteners to be placed far back from the edge making it mandatory to use a large renew: ablepoint comprising a large proportion of the entire'weight of the tooth. V V V As a further drawback in the use of conventional teeth of the renewable type, it has been difficult to obtain firm seating between thetooth base and-the point fastened thereto. It has been found that any relative movement between the two p'ortions of the tooth tends to increase as time goes on tending to destroy the interiitting faces on both the point and the baseandnecessitating eventual replacement of the base portion. In may instances it is recognized that the renewable point should be replaced as soon; as it is no longer effective as a utting edge, but due to the mounting costs of labor and material and the time which is lost in the replacementprocess, such replacement has been frequently delayed at a'large cost in the ef iciency of excavator operation. i

Accordingly, itis an object of the present in- Yention' to provide a renewable dipper tooth which is not dependent upon the use of bolts, pins, keys or other fastening members with their attendant shortcomings, but which includes a fastener of novel construction serving to keep the tooth parts positively assembled and protected against wear and breakage. I

t is another object to provide a renewable point for a'bucket tooth which is small-in size as compared to the base portion thereof so as to reduce the cost and, consequently, justify frequent replacement thereof after moderate wear in. the.

interest of obtaining maximum operating elfi-- ciency.

It is a further object to provide a renewable bucket tooth which may readily be installed or removed in the field with a minimum amount of labor and a minimum of shut-down time for the machine. l'

It is a furter object of the invention to provide a renewable tooth point in which the fastening means is integrally formed and so constructed as not only to enable firm initial seating but also to prevent gradual loosening and the development of play as a result of prolonged heavy duty serv ice. The renewable point disclosed herein becomes even more tightly engaged with the base portion as an incident to use but may nevertheless be removed very readily with the use of a chisel or other simple tool.

Other objects and advantages of the invention will become apparent as the discussion proceeds taken in connection with the accome panying drawings, in which: Figure 1 is a fragmentary view ofth'e lip portion of a bucketfshowing a series of bucket teeth-alined thereon- Fig. 2 shows the tip portion of one of the teethof Fig. 1 in a section taken parallel to the bucket axis. 5

Fig. 3 is a fragmentary view showing the tooth disclosed in Fig. 2 prior to the bending of one of the fastening lugs. I Fig. 4'shows the non-renewable or base portion of a tooth and in particular the fastening recesses formed therein. r Y Fig. '5 is .a sectional view of the renewable point taken along line 55 of Fig.2. 0 Fig. 6 shows insertion of a purposes.

tool for removal Fig. 7 shows a -modification of the present invention in vertical section similar to Fig- 2.

Fig. 8 is a face view of the tooth point of Fig. 8a is a section taken along line W lla. in

Fig. 9 is a fragmentary view of the fastener portion of Fig. 7 prior to bending one of the lugs into its recess.

While the invention is susceptible of various modifications and alternative constructions and uses, I have shown in the drawings and will herein describe in detail only the preferred embodiments of the invention. It is to be understood, however, that I do not intend to limit the invention by such disclosure, but aim to cover all modifications and alternative constructions and uses falling within the spirit and scope of the invention as expressed in the appended claims.

Referring now to Figure 1 the invention will be seen applied to an excavator bucket I having a row of bucket teeth II spaced along the front edge or lip thereof. Each of the teeth has a relatively massive base portion I2 and a tip portion or point It renewably mounted thereon and presenting a relatively sharp leading edge II.

In' order to show the details of construction ofthe renewable point and the means for fastening the same, reference is next made to the transverse sectional view of Fig. 2 where it will be seen that the base portion I2 has a tongue I5 re ceived in the point I4. Each side of the base portion I2 has a recess IS formed therein defining a recessed abutment I8. The front end of the base portion is tapered or charnfered as at IS, the latter portion necking down at a ledge to the tongue i5 which is of lesser cross section. As a more detailed structural feature, the recess I6 has a forward or alining portion IBa the purpose of which will become apparent as the discussion proceeds. I I

To hold the point I4 firmly seated on the base portion I2, the point is provided with "a lug 2| on the front and back sides thereof which is adapted tobe deformed into the recess IS in the base portion and to be in clamping engagement with the abutment I8. In the practice of the invention the lug 2I has a head portion 22 joined integrally with the point I4 by a neck 24. The lug 2 I is thus of flaring cross section providing a gripping surface on the underside thereof and'a face portion 26 facing outwardly of the tooth. The gripping surface 25 is curved or shaped to conform generally to the shape of the abutment ['8 although, as will be noted in Fig. 2, the parts aresha'ped relatively to one another 'so that interference with the abutment I8 takes place first at the lip portion 25a of the surface 25 as the lug'2l is pounded into the seated position. By reason of such construction only'slight inward deformation of the lug 21 is required to cause wedging engagement at the surface 25a, tending to force the point I4 into intimate jammed engagement with the base portion [2 of the tooth. It will be apparent that as the lug 2| is forced more deeply into the recess I6, the wedging or pinching force on the point is progressively increased. 7 v

As shown in the drawing, the head portion 22 ofthe lug is relatively great in cross section as compared to the neck 24. Bending thus takes place almost entirely at the neck since'thisi's the point at which the torque, due to pounding on the surface 26 for exam'ple, is a maximum. "In effect, therefore, the lug is a lever of the second class, causing the force applied at 25 to be greatly in excess of the force required to produce inward deformation of the lug.

In order to further insure that bending takes place at the neck 24, I provide an internal boss 28 immediatelyadjacent thereto. This boss is formed to be received in the portion Ilia of the 4 recess I6 and to seat firmly on the root thereof. The boss 28 thus serves as a rigidly reinforced base to concentrate the bending forces slightly ahead of the region 25a. As a further detail of construction, it will be noted that the parts are proportioned so that a gap 29 exists at the end of the boss 28 so that interference cannot take place at this point. Similarly, a skirt 30 is formed on the point I4 which is separated from the ledge 20 by a space 3|. As a result, substantially all of the force exerted between the gripping surface 25 and the abutment I8 is effective to wedge the point onto the tapered surfaces on the tongue I5 without bottoming taking place in any part of the interfitting structure.

In practicing the present invention, the wedgeshaped lug 2I is so formed that the base portion 26 projects above the surrounding surface to form a projecting hump even when the lug is fully received in its recess. As shown in Fig. 2 such projection or hump is wedge-shaped, extending upwardly away from the base of the tooth proper in a direction away from the cutting point I'I. Each bite of the tooth thus tends to further coinpress the lug 2! due to the crowding of the earth or other material against the face 25. As a; re-

sult, any tendencyof the tip I4 to loosen or develop play as an incident 'to use of the shovel is immediately counteracted by the pressure of the material being dug. Stated another way. any force on the tooth tending to cause play to develop, of itself, causes the tooth to be more firmly united and therefore to maintain its unitary nature until the edge I! is Worn sumcienuy to require replacement, v

The invention is also concerned with rmovlii of the point after it has become worn. without the necessity of unscrewing bolts or removing rivets or pin-type fasteners. It is proposed instead that a tool channel be formed in the base portion of the tooth to cooperate with the under portion of the lug to enable the lug to be bent outwardly away from the tooth body, just the 112- verse of th assembling operation. In the present embodiment as disclosed in Fig. 2 this is accom*- plished by providing an access space 34 between the forward facing wall of the recess It and the lug 2I thereby enabling a chisel 33 or similar tool to be inserted. As disclosed in detail in Flgfi, merely inserting the chisel and pounding the same toward the root of the space 34 is suflicient to wedge the lug 2| upwardly. If desired, the chisel may be employed as a lever pivoting about the region 35. Because of the relatively short spacing between the pivot area 35 and thepresented edge of the lug 2|, it is manifest that substantial leverage may be obtained.

In accordance with one of the more detailed aspects of the invention the lug 2| is undercut along its trailing internal edge to provide-a groove 36. The latter not only increases the width of the space 34 but enables a larger and stronger tool to be inserted. Due to the inwardly'extendjing part of the groove 36, the abutment It the base portionof the tooth is effectively'sliielded against nicking-or other damage fromaninsei' ted chisel. Such groove'36 hasalso-been found to be of considerable help in prying the lug upwardly using the region 3'5-as a fulcrum, since it forms'a firm and substantial seat for any inserted tool.

Turning attention now to Figs. 7,, 8 and-'9 another modification of the invention is shown, be=

ing different from that previously disclosed mi embodiment the base portion of-tiie tooth car ries a point M. The "latter is telescoped over a tapering tonguebl on the baseportion. 'Ihe point is alug of generally T-shap'e'having laterally extending tabs 41. On its underside the lug hasv a gripping l face 46' which is curved to register generally with an abutting surface ll inthebase portion of the tooth." Just as in the previous embodiment, the lug45-is general1y= wedge-shaped, having a neck portion 49 at which most of the bending takes'place. Thus; the" head portion of the lug remains substantially unde-' formed as it is pounded into its seated position.

With the point 4| fully seated, substantially all of the engaging force is borne by the forwardly tapering surfaces of the tongue 42 Sufficient clearance is maintained at the regions 58, 5| and 52 so that bottoming of the point on the base portion cannot occur.

In accordance with one of the more detailed aspects of the invention, the arms of the T-shaped recess 44 are laterally extended beyond'the tabs 41 on the; lug 45. As will'be more clearly, seen by reference to Fig-8, this provides an access space 54. Upon inserting a chisel or similar tool in the space 54, the lug 55 may be wedged or pried upwardly away from the base portion of the tooth in much the same manner as in the embodiment previously discussed. If desired, the base portion of the tooth may have a hole 55 centrally formed therein to provide clearance for both the underside of the lug and for any inserted I tool.

It will be seen that in both of the embodiments the lug is relatively massive and that the point of bending is coordinated in a very efficacious manner with an abutting surface on the base portion of the tooth. In all of the embodiments increased deformation of the lug produces a pinching or wedging effect, causing the tip portion of the tooth to seat more firmly on the base portion. Further, the engagement is not adversely aifected by severe usage but, on the contrary, is increased to a degree which varies proportion ately with the resistance and the density of the material being excavated, employing the crowding action of the earth. Removal in the field in spite of such firm engagement is readily accomplished Without heavy duty tools or tools of special design.

A solid and durable construction is achieved which at the same time enables the replaceable dipper point to be made extremely small relative to the base portion of the tooth. Thus, there is little loss in discarding a point after the cutting edge has become considerably worn and it is no longer necessary, as a matter of economy, to attempt rebuilding the edge portion by welding or brazing. Furthermore, due to its small size, the point may be formed of the newly developed more costly alloys without seriously increasing the amount of the investment per shovel.

While the invention has been described in connection with a tooth for an excavating bucket, it will be apparent that the teachings in their broader aspects are equally applicable not only to other types of earth-engaging apparatus, but also to other types of tools utilizing renewable points which must be replaced from time to time because of wear.

I claim as my invention:

1. A composite bucket tooth having provision for point renewal comprising, in combinatiod'a; relatively massive base having a recess formed in. a lateral wall thereof, a-- tapered tongueon-theend of said base adjacent said recess, a renewable point having a trailing edge and an internal receptable for the mating reception ofnsaid tongue,

ward into said recess so that increased deformation of the lug is accompanied by intimate jam ming of said tapered tongue in said receptacle.

' 2-. A renewable point for a bucket toothor the like having a recess formed on a lateral surface thereof and in which the recess has forward and rear walls arranged in shallow v-formationico'mprising, in combination, a body portion, a retaining lug integrally formed on thetrailing edge of. the body portion so as tobe positioned over said:

recess when said point'and said bucket toothare in engagement, said lug being relatively massive.

and inflexible but havinga neck portionconnecting'it to the point so that'upon inwardideformae. tion of the lugbending occurs at the neck portion: causing initial binding engagement between the forward wall of said recess and the region of the lug'adjacent said neck portion, said lug having a head portion which upon seating of the lug in said recess assumes a position spaced opposite the rear wall thereof for the wedging admission of a cold chisel or the like to facilitate renewal of the point.

3. A renewable point for a bucket tooth or the like having a recess formed on the side thereof comprising, in combination, a body portion, said body portion being hollowed out to provide a receptacle enabling the point to be telescoped over said bucket tooth, a retaining lug integrally formed on the trailing portion of the point so as to be positioned over said recess when said point and said bucket tooth are in engagement, said lug being relatively massive and inflexible but havins aneck portion connecting it to the point, the body portion of said point having formed therein an internal boss reinforcement adjacent said neck portion to insure that application of inward pressure to said lug is accompanied by localized bending at said neck portion.

4. A renewable point for a bucket tooth or the like having a recess formed in a lateral surface thereof comprising a point body having a receptacle formed therein for mating reception of the tooth, said point body having a lug formed at the trailing edge thereof for reception by said lateral recess for locking the point on said base portion, said lug being of generally wedge-shaped crosssection and of such thickness as to present an inclined surface which extends above the surrounding surface of the point even when the lug is fully seated in said recess so that said lug is forced increasingly into said recess by the crowd'- ing action of large rocks and the like during the digging operation.

5. A point for a renewable tooth having a tooth base with a recess formed in a lateral surface thereof, comprising, incombination, a point body shaped to form a hollow receptacle for reception of the end of the tooth base, a lug formed on'the trailing portion of said point and having a flaring cross section to form a neck and a head portion adapted to be forced down into said recess to lock the point on the base, the head portion of the lug QiQQQiQQQ 7 being relieved to provide, a bearing surface spgced from the wall of said rec ss at. a poin mm??? from the neck portion of the lug to facilipa fse insertion or a prying tool for disengeging sold leg from said recess.

6. A composite bucket tooth havin provision for point renewal comprising, in combination, a relatively massive base having a conce ve recess formed in a lateral wallthereof, a tapered tongue on the end of said base adjacent said recess, a renewable point having a cutting edg nd on internal receptacle for the mating reception of said tongue, a lug on the trailing edge of said point, having a relatively inflexible body and e flexible neck portion, said lug being so shaped as to be reeeived in said concave recess. said point having an internal reinforcing boss adjacent said neck portion, such boss and the inflexible nature of the lug body serving to coneentraige bending at said neck portion, the wall of said conceive re: cess being so positioned that the lip portion there: of is engaged vfirst as the lug is pounded down.- wardly into said recess whereby said tapered tongue is jammed intimately into said re ptacl 7 A composite bucket tooth having provision for point renewal comprising, in combination, a relatively massive base having a, concave recess 8 min d in a lat ra W111 th reof, a t erin nsi on we on 9i s le a pbi i ki it a d r cess and o ing; longibiidinel groove'fiherein'; 'g newable mini evee" We g ed e a an nte nelr c esle $0 irs e e i n 9! aid @neueiel'us i jl eireile' e's of s i poi t a d nosi i n d ov r sai r ces a i' 1 8 be n 15. some e8 be'm vea l' f 'e on nwa d de er e ny T p d in e el l -i on ii slinelly axree's ei l ib 'i' nfi aid ue..-.sa bo e e lir serving t6 e ag h oove i v lid P e s: j eem etp q e i u s se vin as r gimens? q dimmed? bending o said .8 i s $5 9 1 i nn' c ooes; he ills ismunded dqwewe d 'v 1 th s id itec FQEEEST'E- MITHJ eereeems (RI-TED Tile following references are of record in one file of this patent:

UNITED STATES Pereme 2392s? sews J'ee- 5 1943