US3881262A

US3881262A - Two-part excavating tool

Info

Publication number: US3881262A
Application number: US378147A
Authority: US
Inventors: Clifford Cullen
Original assignee: Vickers Ruwolt Pty Ltd
Current assignee: Vickers Ruwolt Pty Ltd
Priority date: 1969-09-09
Filing date: 1973-07-11
Publication date: 1975-05-06
Anticipated expiration: 1992-05-06

Abstract

Attaching means for releasably attaching two excavator tool parts, one tool part having a nose portion and the other having a socket for receiving that nose portion. The attaching means including at least one pair of angularly disposed side locking surfaces formed on the nose portion, and a complementary pair of such surfaces formed in the socket, which frictionally engage to hold the two tool parts in assembly. At least one side surface of at least one of the tool parts being contoured to provide restraining means such as to substantially prevent relative lateral movement between the nose portion and the socket when the tool parts are assembled.

Description

United States Patent [1 1 Cullen May 6,1975

1 1 TWO-PART EXCAVATING TOOL [75] Inventor: Clifford Cullen, Doncaster,

Victoria, Australia [73] Assignee: Vickers Ruwolt Proprietary Limited,

Richmond, Victoria, Australia {22] Filed: July 11, 1973 [21] Appl. No: 378,147

Related U.S. Application Data [63] Continuation of Ser. No. 70,396, Sept, 8, 1970,

abandoned.

[30] Foreign Application Priority Data Sept. 9, 1969 Australia 60633/69 [52] US. Cl. 37/142 R; 172/749 [51] int. Cl E021 9/28 [58] Field of Search 37/142 R, 142 A, 141 R, 37/141 T; 172/713, 749; 175/412; 408/231, 232, 713

[56] References Cited UNITED STATES PATENTS 1,262,870 4/1918 Thomson 37/142 R 2,040,085 5/1936 Fykse et a1. 2,050,014 3/1936 Morrison 37/142 R 2,397,521 4/1946 Askue 37/142 R 2,752,702 7/1956 Nelson 37/142 R 3,012,346 12/1961 Larsen 37/142 A 3,073,502 1/1963 Delli-Gatti, Jr. 37/142 R 3,117,386 1/1964 Ferwerda 37/142 R 3,496.658 2/1970 Eyolfson 37/142 R 3,623,247 1/1970 Stepe 37/142 R FOREIGN PATENTS OR APPLlCATlONS 1,175,713 12/1969 United Kingdom,.,......, 37/142 R Primary ExaminerEdgar S. Burr Assistant Examiner-E. H. Eickholt Attorney, Agent, or FirmDiller, Brown, Ramik & Wight [57] ABSTRACT Attaching means for releasably attaching two excavator tool parts, one tool part having a nose portion and the other having a socket for receiving that nose por tion. The attaching means including at least one pair of angularly disposed side locking surfaces formed on the nose portion, and a complementary pair of such surfaces formed in the socket, which frictionally engage to hold the two tool parts in assembly. At least one side surface of at least one of the tool parts being contoured to provide restraining means such as to substantially prevent relative lateral movement between the nose portion and the socket when the tool parts are assembled.

16 Claims, 24 Drawing Figures PATENIEBHAY ems 3.881.262

sum 2 EF 6 26 a: 1.9270 2: 2a 11 a 2 /6 9 11 r I 28 MM ms 1%. Z

M/VENTUR CLIFFORD CULLEN PATENTEB W 5 I975 SHEET 3 BF 6 II I INVENTDR CLIPF'URD CULLEN OQ AJJA ATTO RN EIS PATENTEUHAY 61.975 3,881,262

SHEET UF 6 M/VENTURS CL\PFDRD CULLEM ilw "QTT D QM EYs TWO-PART EXCAVATING TOOL This is a continuation application of application Ser. No. 70,396, filed Sept. 8, 1970 and now abandoned.

This invention relates to means for releasably attaching parts of an excavator device in assembly, and is particularly although not exclusively applicable to two part excavating tools of the kind including an adaptor and a removable point or tooth element. That is, in one form, the invention provides means for releasably retaining those two parts in assembly. The invention is also applicable to attaching protective shrouds to the front edge of a scraper blade or digger bucket base, but it will be convenient to mainly describe the invention in relation to digger teeth.

Two-part excavating tools of the kind indicated are desirable because of their facility to enable replacement of the tooth element, which is of course subjected to the greater wear during use. Difficulty has been experienced however, in providing effective and convenient releasable retaining means for connecting the two parts of such tools. Numerous constructions have been proposed, bit they generally suffer from complexity and/or difficulty of releasing, and in some cases they are only partially effective.

Reference throughout the specification to excavators or excavating equipment is to be understood as embracing all types of earth handling and mineral processing equipment such as scrapers, diggers, dredges (whether for open-cut mining or underwater dredging), earth boring equipment, and tractor mounted buckets, rippers, scraper blades and the like. The invention is particularly applicable to components of excavating equipment which are subjected to a high rate of wear and heavy loading during use, and must be adapted for convenient removal for replacement or repair.

It is a principal object of the present invention to provide improved retention means for excavator devices, and such means which is applicable to a two-part excavating tool. It is a further object of the invention to provide a tool adaptor and/or tooth elemet having such retention means.

It is a still further object of the invention to provide a shroud element having retention means such as to allow ready releasable attachment to an excavator plate member.

Yet another object of the invention is to provide an excavator tool part having retention means such as to not require separate elements such as pins, wedges or bolts to effect secure and releasable attachment to another tool part, but which retention is effected solely through frictional engagement between surfaces having a Morse or similar taper, which is preferably within the region of :l. A further object of the invention is to provide an excavator tool part having such retention means, and also having restraining means which functions to prevent substantial lateral movement between the two tool parts when assembled.

Still a further object of the invention is to provide a two-part excavator tool combination in which the two parts are releasably retained in secure assembly without the aid of separate elements such as pins, wedges, or bolts, but which retention is effected solely by frictional engagement between surfaces having a Morse or similar taper, which is preferably within the region of 20: I. Another object of the invention is to provide such a combination in which restraining means functions to LII prevent substantial lateral movement between the two parts of the assembly.

Another object of the invention is to provide an com bination as aforesaid having the desired retaining and restraining means formed on side surfaces of a nose portion of one tool part, and substantially complemew tary side surfaces of a socket of the other tool part which receives the nose portion, which side surfaces are tapered and frictionally engage to retain the two parts in assembly. It is yet another object of the invention to form the two parts of the combination so that the nose portion is able to move deeper into the socket as wear occurs between engaging surfaces of those members.

The following description refers in more detail to those essential features and further optional featurs of the invention. To facilitate an understanding of the in vention, reference is made to the accompanying draw ings where these features are illustrated in preferred form. It is to be understood however. that the essential and optional features of the invention are not limited to the specific forms of these features as shown in the drawings.

In the drawings:

FIG. 1 is a side elevational view of one embodiment of the invention, and which is partially sectioned for convenience of illustration;

FIG. 2 is a partsectioned plan view of the embodi ment shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken along line lII-lll of FIG. 1;

FIG. 4 is a view similar to FIG. 3, but showing an alternative rib and flute arrangement;

FIG. 5 is an end view of the tooth element ofthe em bodiment of FIG. I;

FIG. 6 is an end view of the adaptor of the embodiment of FIG. 1;

FIG. 7 is an end view of a modified form of the tooth element of FIG. I;

FIG. 8 is an end view of an adaptor for use with the tooth element according to FIG. 7;

FIG. 9 is a view similar to FIG. I, but showing another embodiment of the invention;

FIG. 10 is a part-sectioned plan view of the embodiment of FIG. 9;

FIG. 11 is a transverse cross-sectional view taken along line XI-XI of FIG. 10;

FIG. I2 is a view similar to FIG. Ii but showing a modified form of the FIG. I0 embodiment;

FIG. 13 is a view similar to FIG. II, but showing yet another modification;

FIG. 14 shows still another variation of the construction shown in FIG. II,

FIG. [5 is yet a further modification of the FIG. 11 construction;

FIG. 16 is another possible modification of the FIG. 11 construction;

FIG. 17 is a view similar to FIG. II, but showing an embodiment in which the nose portion of the adaptor is not split into two sections;

FIG. 18 shows a modification of the arrangement shown in FIG. I7;

FIG. 19 is a longitudinal sectional view of a further embodiment of the invention including a plate member and shroud element;

FIG. 20 is a sectioned plan view of the construction shown in FIG. I9;

FIG. 2I is a plan view showing a tooth adaptor and shroud element mounted side by side on a plate member;

FIG. 22 is a transverse cross-sectional view taken along line XXIlXXlI of FIG. I9;

FIG. 23 is a longitudinal cross-sectional view of a modification of the FIG. 19 embodiment; and

FIG. 24 is a transverse cross-sectional view taken along line XXIVXXIV of FIG. 23.

A typical tooth adaptor 2 to which the invention is applicable includes a body portion 3 having a mounting shank 4 extending from a rear side thereof and a nose 5 extending from its front side. The shank 4 and nose 5 extend in opposite directions. and may be in substantial alignment if the nose is formed as a single section. but it is preferred to have the nose formed of two sections 5a and 5b separated longitudinally by a gap 7. Generally. the shank 4 is substantially square or rectan gular in transverse cross-section. although it may be of any other suitable shape. The shank 4 is usually provided with a slot 6 or other aperture to enable the adaptor 2 to be mounted on an excavating device (not shown) such as a bucket or blade.

For convenience. the adaptor 2 will be hereinafter described as having a particular disposition. but it may be mounted on an excavating device so as to have any other desired disposition. Thus. relative terms such as "upper" and "lower". and words of similar import, as used throughout this specification are not to be taken as limiting on the invention.

Each section of the adaptor nose 5 is preferably substantially square or rectangular in transverse crosssection and has upper and lower surfaces and two oppositc side surfaces. The upper and lower surfaces converge away from the adaptor body 3, and it is preferred that the side surfaces converge in a like manner.

In the embodiment of Hg. 1, at least the upper or lower surface of the nose 5 forms part of the locking means for releasably holding the adaptor 2 in assembly with a tooth element 8. and is contoured so as to increase its area for a reason hereinafter made clear. That contouring may take the form of at least one flute or groove 9 formed in the surface and extending generaily in the direction of the adaptor nose 5. It is preferred however. that both the upper and lower surfaces are contoured. and it is further preferred that the side surfaces of the nose 5 also form part of the locking means as hereinafter described.

In accordance with the embodiment of FIG. I, a plurality of flutes 9 are formed in each of the upper and lower surfaces of the nose 5, and the flutes 9 in each surface extend substantially parallel to each other. A rib II is of course defined between each two adjacent flutes 9, and the opposite side faces 12(see FIGS. 3 and 4) ofeach flute 9 preferably slope upwardly away from each other. The slope of each of the side faces I2 may be in the range l5-"5, and is preferably approximately so that the included angle 'A' (see FIG. 3) formed between adjacent faces 12 is approximately 40 in the preferred arrangement. The base of each flute 9 and the land or apex surface of each rib may be substantially flat, although they may be curved if desired and the arrangement is preferably such that a clearance 13 (see FIGS. 3 and 4) remains between the base of each flute 9 and the apex of an associated rib of the tooth element 8, when the two tool parts are assembled. It is also preferred that the depth of each flute 9 is substantially the same as its greatest width i.e.. the width at the top of the flute 9.

The two surfaces of the nose 5 in which the flutes 9 are formed may slope at an angle within the range l6-20 and preferably at an angle of approximately 18, so that the included angle B (see FIG. I between the upper and lower surfaces of the nose 5 is approximately 36 in the preferred embodiment. .It is not necessary however, that the upper and lower surfaces have the same slope, but it is generally convenient to form such a symmetrical arrangement. The slope of each of the four side surfaces of the nose 5 i.e.. two outer surfaces 14 and two inner surfaces [5 may be in the range 25, and is preferably approximately 3 or 4 so that the included angle C (see FIG. 2) defined between any two adjacent side surfaces is approximately 6-8 in the preferred embodiment. As for the upper and lower surfaces, the slope of the side surfaces need not be the same.

A modified form of the above described adaptor 2 is shown in FIG. 8, and in that modification, the flutes 9 and ribs II are of substantially arcuate form in transverse cross-section so as to produce a wave or corrugated form in transverse cross-section. In such an ar rangement the flutes 9 may be relatively shallow compared to their width. and the width of each rib II is preferably less than that of each flute 9.

In either ofthe foregoing embodiments, an outwardly stepped section may be formed on each side surface of the nose 5 so as to define upper and lower locking shoulders I6 and I7 respectively (see FIGS. 6 and 8) which may slope at an angle of between 2(i. but pref erably 4", so as to converge away from the adaptor body 3. It is also preferred that the slope of each of the

shoulders

16 and 17 increases at the front end portion thereof to facilitate location of the tooth element 8 on the adaptor 2.

The tooth element 8 may have the usual blade section 18 and enlarged body portion I9 which includes a socket 21 for receiving the adaptor nose 5. The socket is preferably substantially complementary in shape to the adaptor nose 5 so that in the assembled condition of the two tool parts there is a satisfactory degree of surface contact between the nose 5 and socket 2|. Preferably however. the nose 5 and socket 21 are dimensioned so that the nose 5 does not bottom within the socket 21, and a space 22 always remains between adjacent end faces of the nose 5 and socket 21, and a similar space 23 remains between the adjacent end faces of the respective body portions 3 and 19 (see FIG. 1).

For a two section adaptor nose 5 as in the embodi ments so far described. it is preferred that the socket 21 is also divided into two sections 210 and 21b by a tongue member 24. A strong connection is achieved by forming the tongue member 24 integral with the upper and lower walls of the socket 21. The socket sections 210 and 21b have flutes 25 formed in the upper and lower surfaces thereof to correspond with the ribs II of the adaptor nose 5, and a rib 26 is defined between each two adjacent flutes 25 so as to locate within a respective flute 9 of the adaptor 2. Furthermore, the fluted surfaces of the socket Zl preferably slope at sub' stantially the same angle as the corresponding surfaces of the adaptor nose 5.

It is also preferred that the inner and outer side surfaces 27 and 28 respectively of the socket 21, slope at substantially the same angle as the corresponding side surfaces of the adaptor nose 5. Thus, the cavity 21 and nose 5 are of substantially complementary shape, except for the clearances previously mentioned, and a further clearance 29 preferably provided between the base of each flute 25 and the associated rib 11 (see FIGS. 3 and 4). The tooth elements 8 of FIGS. 5 and 7 are constructed to cooperate with the adaptors of FIGS. 6 and 8 respectively, and the flutes 25 of each tooth element 8 have a transverse cross-sectional shape substantially complementary to that of the ribs 11 of the respective adaptor 2.

It will be appreciated that with the foregoing arrangement, the tooth element 8 may be firmly retained on the adaptor 2 purely by frictional engagement, and separation of the two parts is relatively simple. For example, the parts may be separated by driving a wedge or the like between the adjacent end faces of the two

body portions

3 and 19. Also, in use, the loading on such a tool is usually such that the tooth element 8 is urged more firmly on to the nose 5 of the adaptor 2.

Because of the high pressure existing in practice between the engaging surfaces of the nose 5 and socket 21, the increased area of those surfaces increases the frictional resistance to sliding. In addition, there is a wedging action between the ribs and flutes which also aids to the retention effect of the constructions described.

It will be obvious that the outer side surfaces of the adaptor nose 5 and tooth element socket 21 may be fluted in substantially the same manner as described for the upper and lower surfaces thereof. Similarly for the inner side surfaces of those tool parts. Thus, either or both pair of side surfaces may be fluted additional or alternative to fluting the upper and lower surfaces.

It has been found that the fluted surfaces of the nose 5 and socket 21 need not engage to achieve adequate locking power between the tooth element 8 and adaptor 2. That is, clearance 31 may be provided at the sides of each rib I1 and 26 as shown in FIG. 4, and the locking means is defined by frictionally engaging side sur faces of the nose 5 and socket 21. In fact, suitable retention is obtained with only one pair of side surfaces engaging i.e., surfaces engaging surfaces 27, or surfaces 14 engaging surfaces 28.

The

clearance spaces

13, 22, 23, 29 and 31 (when provided) enable the nose 5 to move deeper into the socket 21 as wear takes place between engaging surfaces of the two tool parts. Thus, the useful life of the assembly is extended.

In both the FIGS. 3 and 4 arrangements, the cooperating flutes and ribs define restraining means which prevents substantial lateral movement of the nose 5 relative to the socket 21. Although the clearance 31 would seem to allow such movement in the FIG. 4 arrangement, the slope of the fluted surfaces is such that in practice, relatively little lateral movement is permitted before surface engagement occurs at the upper or lower fluted surfaces. It is to be understood that the arrangements of FIGS. 3 and 4, although shown in relation to the FIGS. 5 and 7 embodiment, are equally applicable to the FIGS. 6 and 8 embodiment.

FIGS. 9 and 10 show a further embodiment of the in vention which makes use of the fact that side surface engagement alone provides adequate locking between the two tool parts. For convenience of description, components of this embodiment which correspond to components of the FIGS. 1 and 2 embodiment, will be given the same reference numerals except that those numerals will form part of the series 101 to 200 instead of the series I to I00.

Basically, the FIG. 9 embodiment is substantially the same as that of FIG. 1, except for the omission of flutes in the upper and lower surfaces of the nose and cooperating socket 121 of the tooth element 108. The nose 105 is slightly different in that the upper and lower surfaces thereof are substantially parallel adjacent the body portion 103 and converge from that parallel section at an included angle B which may be in the range 20 to 40 inclusive, but is preferably approximately 30. The angle C of the side locking surfaces 114 and of the nose 105 is preferably substantially the same as for the previously described embodiment, and the side locking surfaces 127 and 128 of the socket 121 slope accordingly. The upper and lower surfaces of the socket 121 are preferably arranged substantially complementary to the corresponding surfaces of the adap tor nose 105, but with clearance 113 provided therebetween.

The locking means in this embodiment is constituted solely by the side surfaces 114 and 115 of the adaptor nose 10S engaging corresponding side surfaces 128 and 127 respectively of the socket 121 as shown in FIG. 11. The clearance 113 is provided at the top and bottom surfaces of each of the nose portion sections to allow the nose portion 105 to move deeper into the socket 121 to compensate for wear. Although both pairs of side surfaces are shown engaging in FIG. 11, it has been found that satisfactory retention is achieved with the

surfaces

115 and 127 only engaging as shown in FIG. 13 or

surfaces

114 and 128 only engaging as shown in FIG. 14. That is. FIGS. 13 and I4 show alternative arrangements of the construction according to FIGS. 9 to II.

The restraining means of the FIGS. 9 to II embodiment is preferably defined by contouring of at least one pair of the side locking surfaces. That is, one pair of side surfaces of either the nose portion I05 or the socket 121 may be contoured, but it is preferred that corresponding side surfaces of both tool parts are contoured. In the arrangement according to FIG. II, the

surfaces

115 and 127 have substantially complementary contours, and although the

surfaces

115 and 127 are shown as convex and concave respectively, the reverse may obviously apply. The contoured surfaces may be part cylindrical, and are preferably formed with a radius at least equal to the maximum width of the nose portion 105.

Contouring as shown of course restrains the adaptor nose 105 against substantial lateral movement towards and away from the upper and lower surfaces of the socket 121, and consequently takes the beam loading on the tooth element 108 during use. It will be clear that other forms of contouring may be used to achieve the same purpose, but a curved arrangement as shown is generally found convenient to manufacture.

The modified arrangements shown in FIG. 13 and 14 are contoured substantially as described above, but are distinguished from the FIG. 11 arrangement in that clearance is provided at the outer and inner side surfaces respectively.

A further modification of the FIG. 11 arrangement is shown in FIG. 12, and in that modification the contoured side surfaces 115 have a greater radius than the adjacent contoured surfaces [27. This difference in radii ensures that the surfaces IIS and I27 will not bear at the centre only. which would possibly permit some undesirable lateral movement of the nose portion I05. The contoured surfaces of the arrangements shown in FIG. 13 and I4 may of course be provided with different radii to achieve the same effect.

FIG. I shows another way in which proper hearing may be achieved between contoured surfaces of the adaptor nose I05 and the socket I21. For the purpose of illustration. this modification is shown in relation to the FiG. I3 arrangement, but it is equally applicable to the arrangement of FIGS. II and [4. According to this modification. a fiat 132 is provided in the central region of each surface Hi to provide a clearance with the respective adjacent surface I27.

Still further. ribs Ill and 126 may be formed on the upper and lower surfaces of the adaptor nose I05 and the socket [21 respectively as is shown in FIG. I6, so as to form a further part of the loading means. and again that variation may be applied to any of the arrangements of FIGS. II to I5. If clearance is provided between the ribs III and [26 as shown in FIG. 4, they will not function as part of the locking means. but will nevertheless serve as additional restraining means.

FIGS. 17 and 18 show possible arrangements in which the nose portion 105 is not split longitudinally as previously described. It will be appreciated however. that any of the surface arrangements described for a two piece nose portion 105 will be equally applicable to a single-piece nose portion as shown in FIGS. 17 and I8. FIG. 17 shows an arrangement in which the contoured surfaces are the locking surfaces. whereas in FIG. 18 the side locking surfaces are substantially flat and adjacent upper and

lower surfaces

133 and 134 of the adaptor nose I05 and socket I21 respectively. are contoured but are provided with different radii to form clearance H3. Thus. in the FIG. 18 arrangement. the

surfaces

133 and 134 bear along the side regions only to form the restraining means. whilst forming clearance H3 in the centre region to permit the adaptor nose 105 to move deeper into the socket 121 to compensate for wear. The same effect could be achieved with a flat on each surface 133, and the contours formed with the same radius.

Yet another embodiment of the invention is shown in FIGS. 19 to 22, and in this embodiment the attaching means of the invention is applied to a shroud element 235 for protecting an edge portion of a plate member 236 which may define a scraper blade. the base of a digger bucket. or any similar excavator device. Components of this embodiment which correspond to components of the first described embodiment will be designated by like reference numerals except that they will form part of the series 20I to 300.

Preferably. the body portion 203 of the shroud 235 has a cavity 237 defined therein which receives an edge portion ofthe plate member 236 as is shown in FIG. 19. A nose portion 205 extends rearweardly from the base of the cavity 237 to locate within the socket 221 formed in the front edge surface of the plate member 236. and that nose and cavity may have cooperating and adjacent surfaces according to any of the arrangements previously described. Also. the nose portion may be formed of a single section rather than two sections as shown in FIG. 20. For convenience however. the nose 205 and cavity 221 are shown to be arranged substantially as in the embodiment of FIG. I], and FIG. 22 shows that arrangement as applied to the shroud element 235 and plate member 236.

A recess 238 is preferably provided in both the upper and lower surfaces of the plate member 236 to contain skirt sections 239 of the shroud element 235. In addi tion. a slot 24! may be provided in the plate member 236 to permit a wedge to be driven. or a lever to be ma nipulated, between that member and the shroud elment 235 to effect separation ofthose tool parts. In all other respects. this embodiment is constructed and adapted to function substantially as described in relation to the previous embodiments.

Shroud elements 235 are often mounted between tooth adaptors of the kind previously described. and section of a typical assembly is shown in plan view in FIG. 21. The adaptor 242 is different to those previously described only in that a mounting shank is not provided. but the body portion of the adaptor fits over the plate member 236 and is secured thereto in a known manner by a key 243 and locking wedge 244.

An alternative form of the FIG. 19 to 22 embodiment is shown in FIGS. 23 and 24, and in this modification the cavity 221 is open at its lower side and a resilient pad 245 is located between the plae member 236 and the upper skirt section 239 of the shroud element 235. The pad 245 may be secured by adhesive or other means to either the shroud element 235 or to the plate member 236, and separation of the two tool parts can be effected by driving a wedge or manipulating a lever within the space 246 provided between the lower skirt section 239 and the tongue member 224. Again the surfaces of the nose portion 205 and the socket 221 can be formed in accordance with any of the arrangements previously desscribed.

It will be appreciated that the foregoing embodiments and arrangements represent a very small portion only of the possible applications and forms of the invention. The invention presents a major advance in attaching means for replaceable components of excava tor equipment. because of its relative simplicity and reliability in service. Manufacturers of excavating equipment have long striven to solve the problems overcome by the present invention. and prior attaching means of the kind in question have generally been complex and- /or inefficient in operation. Actual field tests have shown the attaching means of the invention to have far superior holding power than prior arrangements. even without full contact between adjacent locking surfaces.

A person skilled in the art will readily understand that the various angles referred to may be determined according to the particular materials employed to form the tool parts. Consequently. the angles specified herein are to be taken as examples only for parts of forged steel or similar metal. Furthermore, in all embodiments described. the relative positions of the coop erating nose and socket may be reversed. That is. the socket may be provided in the adaptor or shroud element. in which case the nose will be formed on the tooth element or plate member respectively.

Finally. it is to be also understood that various alterations. modifications and/or additions may be introduced in the preferred constructions and arrangement of parts previously described without departing from the spirit or ambit of the invention.

I claim:

1. An excavator tool part adapted for weding engagement with another tool and having a motor external load bearing surface and a socket including locking side surfaces which extend transverse to said major load bearing surface, said locking side surfaces facing in opposite directions, being non-parallel in the direction of engagement with said another tool part and being curved in opposite directions in transverse cross section, at least at their edges, and non-locking socket side surfaces extending transverse to said locking surfaces, said non-locking surfaces facing in opposite directions and being non-parallel in the direction of engagement with said another tool part, and the included angle between said non-locking surfaces is greater than the included angle between said locking surfaces.

2.. A tool part as defined in claim 1 wherein, the included angle between said locking surfaces is in the range 2 to 8 inclusive.

3. A tool part according to claim 2 wherein the included angle between said non-locking surfaces is in the range to 40 inclusive.

4. An excavator tool including two parts held in releasable combination; one part being subjected to wear in use and being replaceable, and having a major external load bearing surface; one said part having a socket. the second part having a nose, said parts being held in combination by frictional wedging engagement of said socket and nose by respective locking surfaces, all of which extend transverse to said major load bearing sur face; each part having at least one pair of said locking surfaces and at least one pair of non-locking surfaces which extend transverse to said locking surfaces, the surfaces of each pair face in opposite directions and are non-parallel in the direction of engagement between said parts; the included angle defined between each pair of locking surfaces being less than the included angle defined between each pair of non-locking surfaces; the surfaces of each pair of locking surfaces being curved in opposite directions in transverse crosssection, at least at their edges; and clearance being provided between opposed non-locking surfaces of said tool parts.

5. An excavator tool part comprising a body portion and a nose portion extending from said body portion for cooperation with a further tool part having a major external load bearing surface; said nose portion having a pair of locking surfaces which extend transverse to said major load bearing surface and a pair of nonlocking surfaces which extend transverse to said locking surfaces; the surfaces of each pair facing in opposite directions and converge in a direction away from said body portion; the included angle defined between said pair of locking surfaces being less than the included angle defined between said pair of nondocking surfaces; and the surfaces of said pair of locking surfaces being curved in opposite directions in transverse crosssection, at least at their edges. whereby said locking surfaces are engageable with substantially complementary surfaces of said further tool part to frictionally retain said tool parts in combination and to restrain said tool parts against substantial relative lateral movement.

6. An excavator tool part according to claim 5, wherein said nose portion is split longitudinally to form two spaced sections thereby defining a figure having eight side surfaces in transverse cross-section of said nose portion, each section including at least one of said locking surfaces.

7. An excavator tool part comprising a body portion having a cavity therein for receiving a portion of a further tool part. said body portion having a major external load bearing surace; said cavity having a pair of locking surfaces which extend transverse to said major load bearing surface and a pair of non-locking surfaces which extend transverse to said locking surfaces; the surfaces of each pair facing in opposite directions and converging in a direction away from the mouth of said cavity; the included angle defined between said pair of locking surfaces being less than the included angle defined between said pair of non-locking surfaces; and the surfaces of said pair of locking surfaces being curved in opposite directions in transverse crosssection, at least at their edges; whereby said locking surfaces are engageable with substantially complementary surfaces of said further tool part to frictionally retain said tool parts in combination and to restrain said tool parts against substantial relative lateral movement.

8. An excavator tool according to claim 7, member said cavity is divided longitudinally by a tongue membere having two lateral side surfaces to form two sections, each section including at least one of said locking surfaces.

9. An excavator tool according to claim 8, wherein the lateral side surfaces of said tongue member converge towards said mouth, each lateral side surface forming an additional locking surface.

10. An excavator tool according to claim 9, wherein said pair of locking surfaces of said cavity are located in opposed relationship to said tongue member.

ll. An excavator too] including two parts held in releasable combination; one of said parts forming a replaceable part and having a major external load bearing surface, and the other said part forming a mounting part; said mounting part comprising a body portion and a nose portion extending from said body portion; said replaceable part having a cavity therein and within which said nose portion is located; said parts being held in combination by frictional wedging engagement between locking surfaces of said nose portion and said cavity respectively. each of said locking surfaces extending transverse to said major load bearing surface; each part having at least one pair of said locking surfaces and at least one pair of non-locking surfaces which extend transverse to said locking surfaces, the surfaces of each said pair face in opposite directions and converge in a direction away from said body portion of the replaceable part; the included angle defined between each pair of locking surfaces being less than the included angle defined between each pair of nonlocking surfaces; the surfaces of each pair of locking surfaces being curved in opposite directions in transverse cross-section, at least at their edges; and clearance being provided between opposed non-locking surfaces of said tool parts.

12. An excavator tool including two parts held in releasable combination; one of said parts forming a replaceable part and having a major external load bearing surface. and the other said part forming a mounting part; said replaceable part having a cavity therein which receives a portion of said mounting part; said parts being held in combination by frictional wedging engagement between locking surfaces of said cavity and said portion respectively, each of said locking surfaces extending transverse to said major load bearing surface; each part having at least one pair of said locking surfaces and at least one pair of non-locking surfaces which extend transverse to said locking surfaces, the surfaces of each said pair face in opposite directions and converge in a direction away from the open mouth of said cavity; the included angle defined between each pair of locking surfaces being less than the included angle defined between each pair of nonlocking surfaces; the surfaces of each pair of locking surfaces being curved in opposite directions in trans verse cross-section, at least at their edges; and clearance being provided between opposed non-locking surfaces of said tool parts.

13. An excavator tool according to claim 12, wherein said mounting part is in the form of a plate member having an edge portion thereof located in said cavity.

14. An excavator tool according to claim 12, wherein the included angle defined between said locking surfaces is within a range of 2 to 8 inclusive and the included angle defined between said non-locking surfaces is within the range to 40 inclusive 15. An excavator tool part adapted for wedging engagement with another tool part and having a major external load bearing surface and locking side surfaces which extend transverse to said major load bearing surface said locking side surfaces facing in opposite directions, being non-parallel in the direction of engagement with said another tool part and being curved in opposite directions in transverse cross-section, at least at their edges, and non-locking side surfaces extending transverse to said locking surfaces said non-locking surfaces facing in opposite directions and being nonparallel in the direction of engagement with said another tool part, the included angle between said nonlocking surfaces is greater than the included angle between said locking surfaces, said included angle between said locking surfaces being in the range of 2 to 8 inclusive, and the included angle between said nonlocking surfaces being in the range of 20 to 40 inclusive.

16. A tool part as defined in claim 15 wherein said locking side surfaces are the only locking means between said tool part and said another tool part.

Claims

1. An excavator tool part adapted for weding engagement with another tool and having a motor external load bearing surface and a socket including locking side surfaces which extend transverse to said major load bearing surface, said locking side surfaces facing in opposite directions, being non-parallel in the direction of engagement with said another tool part and being curved in opposite directions in transverse cross-section, at least at their edges, and non-locking socket side surfaces extending transverse to said locking surfaces, said non-locking surfaces facing in opposite directions and being non-parallel in the direction of engagement with said another tool part, and the included angle between said non-locking surfaces is greater than the included angle between said locking surfaces.

2. A tool part as defined in claim 1 wherein, the included angle between said locking surfaces is in the range 2* to 8* inclusive.

3. A tool part according to claim 2 wherein the included angle between said non-locking surfaces is in the range 20* to 40* inclusive.

4. An excavator tool including two parts held in releasable combination; one part being subjected to wear in use and being replaceable, and having a major external load bearing surface; one said part having a socket, the second part having a nose, said parts being held in combination by frictional wedging engagement of said socket and nose by respective locking surfaces, all of which extend transverse to said major load bearing surface; each part having at least one pair of said locking surfaces and at least one pair of non-locking surfaces which extend transverse to said locking surfaces, the surfaces of each pair face in opposite directions and are non-parallel in the direction of engagement between said parts; the included angle defined between each pair of locking surfaces being less than the included angle defined between each pair of non-locking surfaces; the surfaces of each pair of locking surfaces being curved in opposite directions in transverse cross-section, at least at their edges; and clearance being provided between opposed non-locking surfaces of said tool parts.

5. An excavator tool part comprising a body portion and a nose portion extending from said body portion for cooperation with a further tool part having a major external load bearing surface; said nose portion having a pair of locking surfaces which extend transverse to said major load bearing surface and a pair of non-locking surfaces which extend transverse to said locking surfaces; the surfaces of each pair facing in opposite directions and converge in a direction away from said body portion; the included angle defined between said pair of locking surfaces being less than the included angle defined between said pair of non-locking surfaces; and the surfaces of said pair of locking surfaces being curved in opposite directions in transverse cross-section, at least at their edges, whereby said locking surfaces are engageable with substantially complementary surfaces of said further tool part to frictionally retain said tool parts in combination and to restrain said tool parts against substantial relative lateral movement.

7. An excavator tool part comprising a body portion having a cavity therein for receiving a portion of a further tool part, said body portion having a major external load bearing surace; said cavity having a pair of locking surfaces which extend transverse to said major load bearing surface and a pair of non-locking surfaces which extend transverse to said locking surfaces; the surfaces of each pair facing in opposite directions and converging in a direction away from the mouth of said cavity; the included angle defined between said pair of locking surfaces being less than the included angle defined between said pair of non-locking surfaces; and the surfaces of said pair of locking surfaces being curved in opposite directions in transverse cross-section, at least at their edges; whereby said locking surfaces are engageable with substantially complementary surfaces of said further tool part to frictionally retain said tool parts in combination and to restrain said tool parts against substantial relative lateral movement.

11. An excavator tool including two parts held in releasable combination; one of said parts forming a replaceable part and having a major external load bearing surface, and the other said part forming a mounting part; said mounting part comprising a body portion and a nose portion extending from said body portion; said replaceable part having a cavity therein and within which said nose portion is located; said parts being held in combination by frictional wedging engagement between locking surfaces of said nose portion and said cavity respectively, each of said locking surfaces extending transverse to said major load bearing surface; each part having at least one pair of said locking surfaces and at least one pair of non-locking surfaces which extend transverse to said locking surfaces, the surfaces of each said pair face in opposite directions and converge in a direction away from said body portion of the replaceable part; the included angle defined between each pair of locking surfaces being less than the included angle defined between each pair of non-locking surfaces; the surfaces of each pair of locking surfaces being curved in opposite directions in transverse cross-section, at least at their edges; and clearance being provided between opposed non-locking surfaces of said tool parts.

12. An excavator tool including two parts held in releasable combination; one of said parts forming a replaceable part and having a major external load bearing surface, and the other said part forming a mounting part; said replaceable part having a cavity therein which receives a portion of said mounting part; said parts being held in combination by frictional wedging engagement between locking surfaces of said cavity and said portion respectively, each of said locking surfaces extending transverse to said major load bearing surface; each part having at least one pair of said lockIng surfaces and at least one pair of non-locking surfaces which extend transverse to said locking surfaces, the surfaces of each said pair face in opposite directions and converge in a direction away from the open mouth of said cavity; the included angle defined between each pair of locking surfaces being less than the included angle defined between each pair of non-locking surfaces; the surfaces of each pair of locking surfaces being curved in opposite directions in transverse cross-section, at least at their edges; and clearance being provided between opposed non-locking surfaces of said tool parts.

14. An excavator tool according to claim 12, wherein the included angle defined between said locking surfaces is within a range of 2* to 8* inclusive and the included angle defined between said non-locking surfaces is within the range 20* to 40* inclusive.

15. An excavator tool part adapted for wedging engagement with another tool part and having a major external load bearing surface and locking side surfaces which extend transverse to said major load bearing surface, said locking side surfaces facing in opposite directions, being non-parallel in the direction of engagement with said another tool part and being curved in opposite directions in transverse cross-section, at least at their edges, and non-locking side surfaces extending transverse to said locking surfaces, said non-locking surfaces facing in opposite directions and being non-parallel in the direction of engagement with said another tool part, the included angle between said non-locking surfaces is greater than the included angle between said locking surfaces, said included angle between said locking surfaces being in the range of 2* to 8* inclusive, and the included angle between said non-locking surfaces being in the range of 20* to 40* inclusive.