WO2013067585A1

WO2013067585A1 - An excavator wear assembly

Info

Publication number: WO2013067585A1
Application number: PCT/AU2012/001372
Authority: WO
Inventors: Josua KIRSCH; Douglas WALLIS; Edwin Schuetz; Miguel Guimaraes
Original assignee: Cqms Pty Ltd
Priority date: 2011-11-09
Filing date: 2012-11-08
Publication date: 2013-05-16

Abstract

A lock assembly for an excavator wear assembly, the lock assembly comprising an engagement member having a tensioning aperture passing through a body thereof and an inclined bearing face, and a tensioning member having a threaded portion at a first end which is received in the tensioning aperture, wherein the engagement member further comprises a slot extending through a side wall thereof and opening into the tensioning aperture.

Description

ί

1

TITLE

AN EXCAVATOR WEAR ASSEMBLY FIELD OF THE INVENTION

The Invention relates to an excavator wear assembly. The invention is concerned particularly, although not exclusively, with the mounting of excavator teeth, adaptors and shrouds to excavator buckets.

BACKGROUND TO THE INVENTION

Excavator tooth assemblies mounted to the digging edge of excavator buckets and the like generally comprise a replaceable digging tooth, an adaptor body and an adaptor nose which is secured by welding or the like to the digging edge of a bucket or the like. The tooth generally has a socket-like recess at its rear end to receivably locate a front spigot portion of the adaptor nose and a removable locking pin is generally employed to releasably secure the tooth on the adaptor.

A similar arrangement is found for other excavator wear assemblies such as those including a wing shroud for mounting to a portion, typically a cheek plate, of an excavator bucket to protect that area from excessive wear.

In use, excavator teeth and wing shrouds are subjected to extensive load forces along a longitudinal axis as well as in vertical and transverse directions. For excavator teeth, a snug fit is required between the digging point and the front portion of the adaptor and also between the adaptor socket and the nose spigot portion and their respective mounting pins to avoid premature wear betweerf the components. As the various components wear, the locking pins can loosen thereby increasing the risk of loss of a digging point or an entire adaptor/tooth or shroud combination. This necessitates considerable downtime to replace the lost wear members and if items such as locking pins are not recovered they can cause damage and/or further downtime in downstream operations such as ore crushing and the like.

The greatest loads experienced by excavator tooth assemblies are vertical loads which tend to generate large moment forces capable of rotating a tooth off the front of an adaptor and/or rotating the adaptor off the adaptor nose. In addition, twisting or "yaw" loads are frequently imposed on such tooth assemblies.

Despite many prior art attempts to improve the mounting of a wear member to a nose of an excavator, most of these proposals suffer from one or more deficiencies. As described hereinafter, many of the prior art references relate to direct mounting of a tooth onto a nose without an intermediate adaptor but in those assemblies, the mounting systems for securing teeth directly onto excavator noses is considered analogous to the mounting of a tooth onto an adaptor. Further, the mounting and/or locking assemblies employed for excavator teeth and wing shrouds may be similar and so the following discussion of the prior art, while mostly addressing mounting of excavator teeth assemblies, may be applicable to both.

United States Patent No 4,182,058 describes an excavator tooth having a rearwardly divergent tapering socket to receive a nose having a complementary-shaped front spigot portion. Resistance to rotational moment forces is borne by a resilient steel cotter pin extending through aligned vertical apertures in the socket and spigot portions.

United States Patents 3,774,324, 4,338,736, 4,481,728, 4,903,420, 5,469,648, 7,100,315 and 6,735,890 all describe nose and tooth combinations wherein the nose has a generally convergently tapering spigot portion with a forward tip having a box-like configuration with at least the upper and lower surfaces thereof having faces parallel to each other and to a longitudinal axis of the nose portion. With the exception of Patent No 4,338,736, which describes a transverse locking pin, each of the tooth mounting arrangements is heavily reliant on a large vertical locking pin to resist rotational moment forces tending to rotate the teeth off respective noses.

United States Patent No 4,231 ,173 describes a tapered adaptor nose having a box-like free end, which engages in a mating box-like socket cavity to resist rotational moments. Opposed pairs of rearwardly extending tongues engage in corresponding recesses in the outer surfaces of the adaptor nose to resist rotational movements. Because the tongues themselves are unsupported, they possess a limited capacity to resist rotational moment forces.

United States Patent No 5,272,824 describes a structure similar to that of United States Patent No 4,231 ,173 except that the side tongues are of more robust dimensions and the upper and lower tongues are formed as box-like members with apertures to receive a vertical mounting pin passing through aligned apertures in the tooth and adaptor nose.

United States Patent No 4,404,760 provides flat rail surfaces on the adaptor nose to engage with mating grooves in the socket aperture of a corresponding tooth wherein the mating rail and groove surfaces are generally parallel to the longitudinal axis of the tooth.

United States Patent No 5,423,138 describes a generally tapered nose having a box-like front end with upper and lower transverse surfaces generally parallel to a longitudinal axis of a tooth which located directly thereon. The parallel upper and lower transverse surfaces are contiguous with upper and lower rail surfaces on each, side of the nose and parallel to the longitudinal axis of the tooth. A pair of rearwardly extending side tongues locate in recesses formed in the outer side faces of the nose, ostensibly to resist rotational moment forces in the tooth. Because the side tongues are recessed to accommodate the side rail portions, the robustness of the side tongues is somewhat compromised.

United States Patent No 4,233,761 describes a fairly stubby tapered nose having a box-like front portion with upper and lower surfaces generally parallel to a longitudinal axis of an excavator tooth, an intermediate rearwardly diverging tapered portion and a rear portion having upper and lower surfaces extending generally parallel to a longitudinal axis of the tooth. Formed on the upper and lower surfaces of the front, intermediate and rear portions of the nose are spaced parallel reinforcing ribs which are located in mating grooves in the excavator tooth. A large vertical locking pin extends through aligned apertures in the tooth and nose between the reinforcing ribs. This structure is heavily reliant on the locking pin to resist rotational moment forces however it is considered that this configuration may be prone to failure in the rear portion of the adaptor.

United States Patent No 5,709,043 describes a nose/adaptor combination wherein the adaptor socket tapers convergently towards a box-like front portion having upper and lower bearing surfaces generally parallel to a longitudinal axis of the tooth, a front transverse upright bearing surface and rearwardly divergent bearing surfaces formed at obtuse angles between the converging upper and lower walls and the side walls of the socket, ostensibly to avoid areas of stress concentration. r

United States Patent No 6,018,896 describes a pin/retainer system for locking an excavation tooth onto an adaptor wherein the retainer is inserted in the adaptor and a wedge-shaped pin is driven into aligned apertures in the tooth and adaptor to resiliently engage with the retainer.

United States Publication No US 2002/0000053A1 describes a mechanism for releasably retaining an adaptor into the nose of a bucket lip or the like wherein a tapered threaded socket is non-rotatably located on the inside of an aperture in the side wall of the adaptor. A threaded retaining pin extends through the threaded socket and locates in an aligned aperture in the bucket nose.

United States Patent No 5,337,495 describes a tooth assembly with a two-piece telescopically engageable adaptor secured to a nose with a tapered wedge pin assembly. A similar mounting system is described in United States Patent No 5,172,501 and United States Patent No 6,052,927. Other retention systems for digging points on adaptors or adaptors on noses are described in United States Patents Nos 6,119,378, 6,467,204, and 6,467,203.

Other devices for removably securing replaceable wear elements on earth working equipment such as a retaining pin, a bolt, a pin lock and locking blocks engageable in a top aperture in a wear member are described in United States Patents Nos 3,839,805, 3,982,339, 4,587,751 , 5,088,214 and 5,653,048 respectively.

United States Patent No 5,937,550 describes a lock assembly for releasably securing an adaptor to a nose of an excavator support structure. The lock assembly comprises a body and a base coupled together and adapted for insertion, while coupled together, in a hole in the nose of the support structure. The length of the lock assembly is extended to secure the adaptor and is retracted to release the adaptor. While adequate for securing an adaptor to a nose of an excavator support structure, the lock described in this patent is relatively complex in design and operation leading to high costs and labour intensive extraction procedures in the field.

Canadian Patent Application No 2,161,505 describes a system for removably retaining an excavation point on an adaptor with at least one flanged sleeve having a screw-threaded aperture therein, the flanged sleeve being noh-rotatably locatable in a transverse bore in the adaptor before fitment of the point onto the adaptor. A screw-threaded pin is inserted into the sleeve via an aperture in the point whereby portion of the head of the pin retains the point on the adaptor.

Australian Patent Application No 2003264586 describes a locking pin assembly comprising a body member having a non-circular cross- sectional shape locatable in a bore of complementary shape extending laterally between opposite sides of an excavator lip mounting nose. After locating the body member in the nose aperture, an adaptor can be engaged over the nose with apertures in opposite side walls aligned with the body member. Threaded bolts engage in threaded apertures in opposite ends of the body member, the bolts each having a tapered shank portion with an enlarged boss at a free end thereof, the boss being locatable in a respective aperture in a side wall of said adaptor to prevent the adaptor from disengaging with the nose.

While generally satisfactory for their intended purpose, the abovementioned prior art, and other arrangements of teeth and/or wing shroud assemblies, suffer from one or more shortcomings or disadvantages in terms of inadequate resistance to rotation under the influence of vertical loads applying a rotational moment, a predisposition to premature wear, difficulties in retention of the teeth on noses or adaptors, inadequate locking systems prone to failure and unduly complicated configurations giving rise to increased fabrication costs. OBJECT OF THE INVENTION

It is an object of the invention to overcome or at least alleviate one or more of the above problems and/or provide the consumer with a useful or commercial choice.

DISCLOSURE OF THE INVENTION

In one form, although it need not be the only or indeed the broadest form, the invention resides in an excavator wear assembly comprising: an excavator wear member having a cavity and a receiving passage extending through a body of the excavator wear member, the receiving passage having at least one inclined surface;

a mounting projection having a body located at least partially within the cavity of the excavator wear member and a retaining passage formed within the body; and

a lock assembly having an engagement member with a tensioning aperture passing therethrough to receive a tensioning member, the engagement member having a bearing surface to engage with the inclined surface and the engagement member having a slot extending through a side wall thereof and opening into the tensioning aperture, a first surface and a second surface of the slot which when spaced apart define an open position and when abutting define a closed position;

wherein the tensioning member is adapted to be located through the receiving passage of the excavator wear member and the retaining passage of the mounting projection and wherein application of a compression force to the bearing surface causes the engagement member to move from the open position towards the closed position.

In a further form, the invention resides in a method of securing an excavator wear member to a mounting projection, the method comprising the steps of:

fitting the excavator wear member onto at least a portion of a body of the mounting projection;

locating a tensioning member through a receiving passage formed through a body of the excavator wear member, the receiving passage having an inclined surface, and through a retaining passage of the adaptor; locating a threaded end of the tensioning member within a tensioning aperture of an engagement member, the engagement member having a bearing face complimentary to the inclined surface and a slot extending through a side wall of the engagement member and opening into the tensioning aperture, a first surface and a second surface of the slot which when spaced apart define an open position and when abutting define a closed position; and

applying torque to the tensioning member to wedgingly engage the bearing face of the engagement member with the inclined surface of the receiving passage to cause the engagement member to move from the open position towards the closed position to thereby secure the excavator wear member to the adaptor.

Suitably, movement of the engagement member from the open position towards the closed position will result in a decrease in the diameter of the tensioning aperture.

Preferably, movement of the engagement member from the open position towards the closed position will result in a wall of the tensioning aperture coming into fnctional engagement with the tensioning member.

In a further form, the invention resides in an excavator wear member comprising:

a body having opposed side walls defining a cavity and one of the side walls having an inwardly convergent portion;

a pair of receiving passages extending through each of the opposed side walls and each having an inclined surface.

Preferably, the inclined surface is an inwardly convergent ceiling.

Preferably, the inwardly convergent portion of the side wall is adjacent an opening of the receiving passage into the cavity.

Suitably, an extending wall projects into the cavity in a region between the receiving passages.

Preferably, the extending wall intersects the inwardly convergent portion of the side wall.

In a further form, the invention resides in a lock assembly for an excavator wear assembly, the lock assembly comprising:

an engagement member having a tensioning aperture passing through a body thereof and an inclined bearing face; and

a tensioning member having a threaded portion at one end which is received in the tensioning aperture;

wherein the engagement member further comprises a slot extending through a side wall thereof and opening into the tensioning aperture.

Preferably, the body of the engagement member adjacent the slot is resiliently deformable to narrow the width of the slot.

Preferably, the slot has a first surface and a second surface which when spaced apart define an open position and when abutting define a closed position. Preferably, the first surface is an upper surface and the second surface is a lower surface.

Suitably, a compression force applied to the bearing face causes the engagement member to move from the open position towards the closed position.

The tensioning aperture preferably has a threaded portion that corresponds to the threaded portion of the tensioning member.

Preferably, the tensioning member has a threaded portion at opposing ends, each threaded portion being received in a tensioning aperture of a separate engagement member.

Suitably, the engagement members comprise an inclined wedging face opposite the bearing face.

Preferably, the tensioning member has a shank extending between the threaded portions, the shank located on a locating surface of a body member.

Preferably, the body member further comprises a ramp surface at opposing ends.

Preferably, the wedging face of the engagement member is located on the ramp surface of the body member. Suitably, the bearing face and wedging face of the engagement member are convergent toward the shank of the tensioning member.

Preferably, the ramp surface of the body member is outwardly divergent.

Preferably, the tensioning member comprises a female tensioning recess at one end.

Tensioning of the tensioning member causes each engagement member to move from the open position towards the closed position.

Further features of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect preferred embodiments of the invention will be described by way of example only with reference to the accompanying drawings, wherein:

FIG 1A shows a perspective view of an excavator wear assembly according to an embodiment of the invention;

FIG 1 B shows an exploded perspective view of the excavator wear assembly shown in FIG 1A;

FIG 1C shows a perspective view of an excavator bucket and lock assembly forming part of the excavator wear assembly shown in FIG 1 A;

FIG 2A shows a perspective view of an excavator wear member and lock assembly forming part of the excavator wear assembly shown in FIG 1A; FIG 2B shows an elevated perspective view of the excavator wear member and lock assembly shown in FIG 2A;

FIG 3A shows a perspective view of the lock assembly seen in FIG

1A;

FIG 3B shows an exploded perspective view of the lock assembly shown in FIG 3A;

FIG 3C shows a perspective view of an engagement member forming part of the lock assembly shown in FIG 3A; and

FIG 4 shows an exploded perspective view of the excavator wear assembly shown in FIG 1A.

DETAILED DESCRIPTION OF THE INVENTION

The excavator wear assembly and lock assembly discussed herein are described with reference to an excavator wear member in the form of a wing shroud releasably secured to one or more mounting projections formed on a lip of an excavator bucket cheek plate. A skilled addressee will appreciate that the invention may also be employed to releasably secure a releasable adaptor to a nose or a releasable tooth directly to a nose of an excavator bucket lip and the like.

Furthermore, the lock assembly may be utilized in other applications such as a retaining pin for components in dragline excavator rigging and the like.

FIG 1A shows a perspective view of an excavator wear assembly 1000 according to an embodiment of the invention. FIG 1 B shows an exploded perspective view of the excavator wear assembly 1000 shown in FIG 1A. FIG 1C shows a perspective view of an excavator bucket 400 and lock assembly 100 forming part of the excavator wear assembly shown in FIG 1A. Excavator wear assembly 1000 comprises a lock assembly 100 adapted to releasably secure a wear member in the form of a wing shroud 200 mountable on one or more adaptors in the form of mounting projections 300 which extend from and may be integral with an excavator bucket 400 and, particularly, a cheek plate 4 0 thereof.

The mounting projections 300 extend from an edge face 411 of the cheek plate 410 and have a body 310 with a convergent face 311 which is inwardly convergent towards an end face 312 thereof. A retaining passage 313 passes through the body of the mounting projections 300 and is adapted to receive a portion of the lock assembly 100 as will be discussed in greater detail below. The excavator bucket 400 is further provided with a nose 420 for the mounting of replaceable teeth (not shown) and a lip 430.

In the embodiment shown, the wing shroud 200 is adapted to be mounted on two of the mounting projections 300. The wing shroud 200 has a body 210 which is generally V-shaped due to a divergence formed by two opposed side walls 211 and further has an outer surface which is a wear surface 212. A cavity 220 is formed between the opposed side walls 211 in which the mounting projections 300 are received. Two locking apertures 230 are formed in the body 210 of the wing shroud 200 and pass through each opposed side wall 211 such that aligned pairs of locking apertures are formed. One or more hoist loops 240 are located on an outer surface of opposed side walls 211 to enable ease of handling by a hoist during attachment and removal operations.

FIG 2A shows a perspective view of the wing shroud 200 and the lock assembly 100 forming part of the excavator wear assembly shown in FIG 1A. FIG 2B shows an elevated perspective view of the wing shroud 200 and the lock assembly 100 shown in FIG 2A.

The cavity 220 is defined, in part, by an inwardly convergent wall in the form of an inclined side wall portion 212 of which there are two, each formed adjacent the lower extent of the opening of the locking aperture 230 into the cavity 220. The convergent face 311 of each mounting projection will abut against the corresponding inclined side wall portion 212. An extending wall in the form of a cavity inner wall 213 extends across the width of the cavity 220 to separate each of the locking apertures 230 on the same opposed side wall 211 and intersect their associated inclined side wall portion 212.

The locking apertures 230 are defined by an inwardly convergent receiving passage 250 which extends through the body of the wing shroud 200 and has a curved floor 251 , an inclined surface in the form of a convergent ceiling 252, and straight side walls 253 and 254. The locking apertures 230 are seen to open into the cavity 220 which has an angled floor adapted to accommodate the end faces 312 of the two mounting projections 300. One of the locking apertures 230 has an extended region 231 for insertion of a tool or the like.

The lock assembly 100 is adapted to sit within the aligned locking apertures 230 and is shown in greater detail in FIGs 3A, 3B and 3C. FIG 3A shows a perspective view of the lock assembly 100, FIG 3B shows an exploded perspective view of the lock assembly shown 100 and FIG 3C shows a perspective view of a component of the lock assembly 100.

The lock assembly 100 has a body member 110, a tensioning member 120, a first engagement member 130 and a second engagement member 140. The body member 110 has an arcuate base 111 adapted to be located on the curved floor 251 of the receiving passage 250 and a locating surface 112 to receive the tensioning member 120. A first ramp surface 113 and a second ramp surface 114, both of which are outwardly divergent, are in contact with the first and second engagement members, 130 and 140, respectively. Opposed rails 115 sit either side of the locating surface 1 2 to effectively form a cradle to accommodate the tensioning member 120 and join first and second ramp surfaces, 113 and 114, at a stepped region 116.

The tensioning member 20 may take the form of a bolt and has a central shank 121 ending in first and second threaded portions, 122 and 123, respectively, which are received in the first and second engagement members, 130 and 140, respectively. The first threaded portion 122 may present right handed turns while the second threaded portion may present left handed turns, or wee versa. The first and second threaded portions, 122 and 123, end in bevelled edges 124 leading into an end face 25 at one end of the tensioning member 120 and a female tensioning recess 126 at the other end. The female tensioning recess 126 is shaped to receive a tensioning tool (not shown) for rotation of the tensioning member 120. The first and second threaded portions, 122 and 123, may have thread depths that become shallower towards the central shank 121. A benefit of this is that the friction between the first and second threaded portions, 122 and 123, and the first and second engagement members, 130 and 140, respectively is increased, which reduces the risk of loosening during use due to vibration.

The first and second engagement members, 130 and 140, are identical in structure and so the components thereof will be described with numerals provided for both with the first number relating to components of the first engagement member 130 and the second number relating to components of the second engagement member 140.

The first and second engagement members, 130 and 140, have a generally square wedge body, 131 and 141 , through which a tensioning aperture, 132 and 142, passes to receive the first and second threaded portions, 122 and 123 respectively, of the tensioning member 120. An inclined bearing face in the form of upper convergent face, 133 and 143, is adapted to be located in wedging engagement with the convergent ceiling 252 of the receiving passage 250 while an inclined wedging face in the form of lower convergent face, 134 and 144, is adapted to sit in wedging engagement with the first and second ramp surfaces, 113 and 114, respectively.

A slot, 135 and 145, is seen to extend through a straight side wall, 136 and 146, of the engagement members, 130 and 140, to open into the tensioning aperture, 132 and 142. The position shown in FIG 3C wherein the slot 135 is open with the two surfaces, a first surface in the form of an upper surface and a second surface in the form of a lower surface, defining the slot 135 spaced apart may be referred to as the open position. The slot, 135 and 145, allows the two portions of the side wall, 136 and 146, either side thereof to be resiliently deformable in that a compression force on one or both of the upper and lower convergent faces, 133, 143 and 134, 144, will result in a narrowing of the slot, 135 and 145, to bring the upper and lower surfaces defining the slot 135 closer together. When these two surfaces abut, this may be referred to as the closed position.

A compressing force on one or both of the upper and lower convergent faces, 133, 143 and 134, 144, causes the upper and lower surfaces defining the slot, 135 and 145, to move from the open position towards the closed position and a concomitant lessening of the diameter of the tensioning aperture, 132 and 142, is seen due to the slot, 135 and 145, opening into it. The closed position wherein the two surfaces defining the slot, 135 and 145, actually abut may or may not be reached depending on the diameter of the tensioning member 120, the size of the compression force and the biasing strength of the side wall, 136 and 146. So long as the engagement members, 130 and 140, move towards the closed position from the open position the required clamping force will be exerted on the tensioning member 120 to greatly reduced the risk of over-tightening of the lock assembly 100.

The engagement members, 130 and 140, have a straight side wall, 138 and 148, with chamfers, 137 and 147, and are oriented relative to one another such that the slot 135 of the first engagement member 130 is on an opposite side of the lock assembly 100 to the slot 145 of the second engagement member 140.

FIG 4 shows an exploded perspective view of the excavator wear assembly 1000 shown in FIG 1A and enables the interaction, in use, of the various components to be envisaged. The wing shroud 200 is mounted on two of the mounting projections 300 such that each of the two locking apertures 230 are in alignment with the corresponding retaining passage 313 and the end face 312 of the mounting projections, which are mounting projection bearing faces, abut the floor 221 of the cavity 220 of the wing shroud 200. The body member 110 with the tensioning member 120 resting on the locating surface 112 is then inserted through the aligned locking apertures 230 formed in the opposed side walls and retaining passage 3 3. The first and second engagement members, 130 and 140, will then be located and threadedly engaged on the respective first and second threaded portions, 122 and 123.

1

In another embodiment (not shown), one of the first or second engagement members 130 and 140 is threadedly engaged with the respective first or second threaded portion, 122 and 123, prior to being inserted through the aligned locking apertures 230 formed in the opposed side walls and retaining passage 313, the other of the first or second engagement members 130 and 140 is threadedly engaged with the respective first or second threaded portion, 122 and 123 after the body member 110 and tensioning member 120 are inserted through the aligned locking apertures 230 formed in the opposed side walls and retaining passage 313.

A male end of a tensioning tool (not shown) is then inserted into the female tensioning recess 126 and the tensioning member 120 rotated such that both of the first and second engagement members, 130 and 140, are drawn along the length of the corresponding first or second threaded portion, 122 or 123, with which they are threadedly engaged via tensioning aperture, 132 or 142. Due to the handedness of the threads they both travel inwardly towards the shank 121. This movement causes the upper convergent face, 133 and 143, of the engagement members, 130 and 140, to be forced into increasing wedging engagement with the convergent ceiling 252 of the corresponding receiving passage 250. Simultaneously, the lower convergent faces, 134 and 144, of the engagement members, 130 and 140, are forced into increasing wedging engagement with the corresponding first or second ramp surfaces, 113 or 114.

This wedging engagement of the first and second engagement members, 130 and 140, with walls of the receiving passages 250 will increase until the compression force felt by the upper, 133 and 143, and lower, 134 and 144, convergent faces is such that the side wall, 136 and 146, having the slot, 135 and 145, formed therein is compressed to narrow the width of the slot, 135 and 145, thereby causing each engagement member, 130 and 140, to move from the open position towards the closed position. As the slot, 135 and 145, is continuous with the tensioning aperture, 132 and 142, the diameter of the respective tensioning aperture, 132 and 142, is caused to decrease. The threaded surface of the tensioning aperture, 132 and 142, effectively clamps onto the respective threaded portion, 122 or 123, of the tensioning member 120 to thereby resist any further rotation thereof and limit the tensioning which can be applied. The tension at which this clamping effect is achieved can be rated by choice of the material from which the first and second engagement members, 130 and 140, are constructed as well as the design thereof.

The locking system described provides a number of advantages in use. When tensioning a bolt as part of a locking mechanism, in the general manner described above, it is important to avoid over-tensioning which transfers excessive bending loads onto the bolt and can cause failure of this or other system components thereby necessitating operational downtime for removal and replacement. The present lock assembly 100 inhibits this by placing a reactionary clamping force on the threaded portions, 122 and 123, of the tensioning member 120 to prevent further torque being applied via rotation of the tensioning member 120. The clamping effect also acts to resist loosening of the lock assembly 100 by frictionally resisting forces which might cause the engagement members, 130 and 140, to move outwardly from the wedging engagement. Direct application of sufficient torque to the tensioning member 120 via the tensioning tool will overcome this resistance and thereby allow for removal of the lock assembly 100.

In this way, the invention provides for an effective method of releasably securing the wing shroud 200 to the mounting projections 300. It will be appreciated that the principle of operation described herein may be applied to the mounting of a range of components onto various structures such as teeth and adaptors or nose and shroud arrangements.

Throughout the specification the aim has been to describe the invention without limiting the invention to any one embodiment or specific collection of features. Persons skilled in the relevant art may realize variations from the specific embodiments that will nonetheless fall within the scope of the invention.

In this specification, the terms "comprise", "comprises", "comprising" or similar terms are intended to mean a non-exclusive inclusion, such that a system, method or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

Claims

1. A lock assembly for an excavator wear assembly, the lock assembly comprising:

an engagement member having a tensioning aperture passing through a body thereof and an inclined bearing face adapted to engage with a receiving passage of a wear member; and

a tensioning member having a threaded portion at a first end which is received in the tensioning aperture;

2. A lock assembly as claimed in claim 1 , wherein the body of the engagement member adjacent the slot is resiliently deformab!e to narrow the width of the slot and wherein the slot has a first surface and a second surface which when spaced apart define an open position and when abutting define a closed position, such that a compression force applied to the inclined bearing face causes the engagement member to move from the open position towards the closed position.

3. A lock assembly as claimed in claim 1 or claim 2, wherein the tensioning aperture has a threaded portion that corresponds to the threaded portion on the tensioning member.

4. A lock assembly as claimed in any one of claims 1 to 3, wherein the tensioning member has a second end having a threaded portion, each threaded portion being received in a tensioning aperture of a separate engagement member.

5. A lock assembly as claimed in claim 4, wherein the tensioning member has a shank extending between the threaded portions, and wherein the shank is located on a locating surface of a body member. 6. A lock assembly as claimed in claim 5, wherein the engagement members comprise an inclined wedging face opposite the bearing face.

7. A lock assembly as claimed in claim 6, wherein the body member comprises a ramp surface at opposing ends.

8. A lock assembly as claimed in claim 7, wherein the wedging face of the engagement member is located on the ramp surface of the body member.

9. A lock, assembly as claimed in claim 7 or claim 8, wherein the bearing face and wedging face of the engagement members are convergent toward the shank of the tensioning member.

10. A lock assembly as claimed in any one of claims 7 to 9, wherein the ramp surface of the body member is outwardly divergent.

11. A lock assembly as claimed in any one of claims 5 to 10, wherein the thread depth of the threaded portions decreases towards the shank.

12. A lock assembly as claimed in any one of claims 4 to 11 , wherein tensioning of the tensioning member causes each engagement member to move from the open position towards the closed position.

13. A lock assembly as claimed in any one of claims 4 to 12, wherein one of the first and second end threaded portions of the tensioning member comprises a right handed thread and the other of the first and second end threaded portions of the tensioning member comprises a left handed thread.

14. A lock assembly as claimed in any one of claims 1 to 13, wherein the tensioning member comprises a female tensioning recess at one end. 15. An excavator wear assembly comprising:

an excavator wear member having a cavity and a receiving passage extending through a body of the excavator wear member, the receiving passage having at least one inclined surface; a mounting projection having a body located at least partially within the cavity of the excavator wear member and a retaining passage formed within the body; and

16. A method of securing an excavator wear member to a mounting projection, the method comprising the steps of:

locating a tensioning member through a receiving passage formed through a body of the excavator wear member, the receiving passage haying an inclined surface, and through a retaining passage of the adaptor; locating a threaded end of the tensioning member within a tensioning aperture of an engagement member, the engagement member having a bearing face complimentary to the inclined surface and a slot extending through a side wall of the engagement member and opening into the tensioning aperture, a first surface and a second surface of the slot which when spaced apart define an open position and when abutting define a closed position; and

17. A method as claimed in claim 16, wherein the movement of the engagement member from the open position towards the closed position results in a decrease in the diameter of the tensioning aperture causing a wall of the tensioning aperture to frictionally engage with the tensioning member. 8. An excavator wear member comprising :

19. An excavator wear member as claimed in claim 18, wherein the inclined surface is an inwardly convergent ceiling. 20. An excavator wear member as claimed in claim 18 or claim 19, wherein the inwardly convergent portion of the sidewall is adjacent an opening of the receiving passage into the cavity.

21. An excavator wear member as claimed in any one of claims 18 to 20, wherein an extending wall projects into the cavity in a region between the receiving passages.

22. An excavator wear member as claimed in claim 21 , wherein the extending wall intersects the inwardly convergent portion of the sidewall.