Technical Field

The disclosure relates to excavation tooth assemblies, lock assemblies for use in such tooth assemblies and to components of such excavation tooth and lock assemblies. The disclosure has application in land based digging equipment and is herein described in that context. However, it is to be appreciated that the disclosure has broader application for example in waterborne excavation equipment such as dredgers, and is therefore not limited to that application.

Background

Excavation teeth are provided on the digging edge of various pieces of digging equipment such as the buckets of front end loaders. Each excavation tooth is formed of a number of parts, commonly a point, an adapter and a lock. The adapter is typically fitted to the excavation equipment and the point fits over the adapter and is retained in place by the lock. In some instances one or more intermediate parts may be also included between the point and the adapter. For ease of description it is to be understood that, unless the context requires otherwise, the term "adapter" used in this specification includes both the adapter arranged to be fitted to the excavation equipment or, if one or more intermediate parts are provided, to that intermediate part(s) or to the combination of the adapter and the intermediate part(s).

The reason that the excavation tooth is formed of a number of parts is to avoid having to discard the entire tooth when only parts of the tooth, in particular the ground engaging part of the tooth (i.e. the point) is worn or broken.

Various types of locks, points and adapters are known. However, it is always desirable to design new excavation tooth assemblies and parts thereof.

Summary of Disclosure

In one aspect of the disclosure, there is provided an excavation tooth lock assembly to lock a first tooth member to a second tooth member, the first tooth member having a body that incorporates a socket which is configured to receive a nose portion of the second tooth member, a locking space provided when the second tooth member is received in the first tooth member, wherein the lock assembly comprises a lock which is configured to be inserted into the locking space in an operative position to lock the first tooth member to the second tooth member, and inter-engaging elements disposed on the lock and one or both of the first and second tooth members, the elements configured to engage to releaseably retain the lock within the locking space in its operative position. The inter-engaging elements may be male and female elements such as for example a detent and a recess.

The excavation tooth assembly typically has a forward end (which is disposed towards or at a digging end of the assembly) and an opposite rear end which fits to the excavation equipment or which receives an adapter fitted to the equipment. In a particular form, the locking space may be formed, at least in part, by surfaces of the first and second tooth members which are disposed to face laterally relative to the forward and rear ends of the tooth assembly and which are arranged in opposing relation to one another.

At least one of the inter-engaging elements may be provided on one of the laterally facing surfaces defining at least part of the locking space.

The first tooth member may comprise an ear that projects away from the socket and which incorporates one of the laterally facing surfaces. In one form, the laterally facing surface incorporated on the ear includes one of the inter-engaging elements.

In one form, the interengaging elements comprise a detent formed on the surface of the first or second tooth member and a recess that is formed in the lock and arranged to receive the detent to releaseably retain the lock within the locking space in its operative position.

According to another aspect of the disclosure, there is provided an excavation tooth lock assembly to lock a first tooth memberto asecond tooth member, the first tooth member including a socket which is configured to receive a nose portion of the second tooth member, a locking space provided when the second tooth member is received in the first tooth member, wherein the lock assembly comprises a detent formed on the surface of the first or second tooth member and a lock which is configured to be inserted into the locking space in an operative position to lock the first tooth member to the second tooth member, wherein the lock comprises a recess that is arranged to receive the detent to releaseably retain the lock within the locking space in its operative position.

In one form, the locking space is defined at least in part by one or more surfaces of the first tooth member and one or more surfaces of the second tooth member.

In one form, according to either aspect described above, the first tooth member may be a point comprising a body incorporating a first digging end and an opposite second end that incorporates the socket. In this embodiment the second tooth member is an adapter.

In another embodiment, the first and second tooth members each form part of an adapter arranged to receive a point.

According to a further aspect of the disclosure, there is provided a lock for locking a first tooth member to a second tooth member in assembling an excavation tooth, the lock comprising a body for inserting into a locking space formed between the tooth members and a recess for receiving a detent of the first or second tooth members to releaseably retain the lock in the locking space.

In one form, a portion of the lock comprising the recess is movable relative to the lock body so as to facilitate engagement of the detent within the recess in installation of the lock in the locking space.

In one form, the portion of the lock comprising the recess is movable between a retracted and an extended position relative to the lock body. In a particular form, the lock portion is biased into its extended configuration. In use with this arrangement, the recess may be retracted to allow receipt of the detent into the recess and when received therein, the portion of the lock incorporating the recess may move to or towards its extended state to capture the detent within the recess.

The lock may comprise a resilient member and the recess is formed in the resilient member. In one form, deformation of the resilient member enables movement of the recess between the retracted and extended position.

The resilient member may be mounted to the lock body. In one form, the resilient member is formed as an insert that is arranged to be mounted within a compartment provided in the lock body.

The insert may be retained in the compartment by a securing mechanism.

The securing mechanism may comprise at least one tab formed on the insert or the lock body arranged to mate with at least one corresponding depression formed in the insert or the lock body.

In one form, the resilient member comprises an elastomeric block and a bearing member which is mounted on the block. The bearing member incorporates the recess and is formed from a hardened material such as steel. In this arrangement the movement of the recess is provided by resilient deformation of the elastomeric block. In a particular form, the elastomeric block biases the recess into its extended position and movement of the recess to the retracted position is caused by compression of the block.

The recess may be an elongate slot.

The recess may be elongate in a direction transverse to the longitudinal extent of the body.

In another embodiment, the recess may be elongate in the longitudinal direction of the lock.

The recess may be located at an intermediate portion of the lock.

The lock may also comprise a groove which is configured to enable the lock to clear the detent when inserting the lock into and removing the lock from the locking space between the tooth members, the groove may be formed in the lock body.

The groove may extend in the longitudinal direction of the lock body.

The recess may be elongate in a direction transverse or parallel to the groove. The groove may comprise groove portions extending from either side of the recess.

A first groove portion may widen at its distal end from the recess.

A second groove portion may widen at its proximal end to the recess.

In a particular form, the portion of the lock (in one form being the resilient member) incorporating the recess is disposed in the lock body so as to be in general alignment with the groove. In one form the lock portion interrupts the groove so as to separate the groove into the first and second groove portions.

In one form, the recess is defined between two shoulder elements disposed on the lock portion. In a particular form, opposing inner surfaces of the shoulder elements define the sides of the recess.

In a particular form, at least one of the shoulder elements is formed as a projection on the lock portion.

In a particular form, an outer surface of that projecting shoulder element forms a ramp surface for aiding the lock in passing over the detent as the lock is inserted into the locking space before thethe detent is captured in the recess.

In a particular form, the lock portion is set into the groove of the lock body so that when the recess is in its extended position, the shoulder elements defining the recess are disposed at or below the outer periphery of the lock body. In this arrangement, when the recess moves to its retracted position, the lock portion moves further into the groove so that the shoulder elements drop further below the outer periphery of the lock body.

The lock may also comprise a tooth member bearing surface for bearing against a surface defining the locking space. In one form, the surface on which the tooth bearing member engages the tooth member on which the detent is not located.

In one form the tooth member bearing surface is angularly spaced about the longitudinal axis of the lock from the recess. In a particular form this angular spacing is in the range of 75 and 105 degrees. In one form the angular spacing is about 90 degrees.

In a particular form the tooth member bearing surface is disposed on the portion of the lock incorporating the recess.

In one form, the tooth member bearing surface is formed on a projection which extends from the lock body. In a particular form, where the lock portion incorporating the recess is in the form of a resilient member, this bearing surface may be formed as part of the bearing member mounted to the elastomeric block.

In one form, the projection incorporating the tooth member bearing surface is movable relative to the lock body between a retracted and extended position. In a particular form this movement may be catered for by deformation of the elastomeric block.

In a particular form, where the projection incorporating the tooth member bearing surface and the recess are disposed on the bearing member, the bearing surface and the recess may move together as they move to into their retracted positions on installation of the lock in the locking space. In one form, the recess is arranged to be slightly offset from the groove formed in the lock body when the tooth member bearing surface and the recess are in their extended position, and is caused to move more into alignment with that groove as the tooth bearing member surface is depressed.

According to a further aspect of the disclosure, there is provided an excavation tooth member comprising a body incorporating a first end, an opposite second end that incorporates a socket configured to receive a nose portion of a further tooth member, and a surface that in use forms part of a locking space arranged to receive a lock, the surface including a detent that forms part of a lock assembly to releaseably retain the lock in the locking space.

The tooth member may comprise an ear that projects from the second end adjacent the socket and the surface which includes the detent may be formed on the ear.

The tooth member may have a forward end and a rear end and the surface which includes the detent may face laterally relative to the forward and rear ends.

The detent may be elongate in the general longitudinal direction of the tooth member.

In another embodiment, the detent may be elongate in a direction transverse to the longitudinal direction of the tooth member

The tooth member may comprise a further ear that projects from the second end adjacent the socket. The further ear may have a surface that in use forms part of a further locking space arranged to receive the lock and includes a further detent that forms part of a lock assembly to releaseably retain the lock in the locking space.

The ear and the further ear may be located on opposite sides of the tooth member.

According to a further aspect of the disclosure, there is provided an excavation tooth member for coupling to a further tooth member in assembling an excavation tooth, the tooth member comprising a a socket for receiving a nose portion of the further tooth member, the tooth member also comprising a detent for being received in a recess of a lockfor locking the tooth member to the further tooth member.

The tooth member may comprise a wall extending away from the socket.

The detent may be formed on the wall.

The detent may be elongate in the general longitudinal direction of the tooth member.

The tooth member may comprise a further detent for being received in a recess of a lock for locking the tooth member to the further tooth member.

The tooth member may comprise a further wall extending away from the socket, the further detent formed on the further wall.

The wall and the further wall may be located on opposite sides of the tooth member. According to a further aspect of the disclosure, there is provided an excavation tooth assembly comprising a a tooth member according to any one of the above aspects of the disclosure and a lock for locking the tooth member to afurther tooth member.

The lock may be a lock according to the second aspect of the disclosure.

According to another aspect of the disclosure, there is provided an excavation tooth assembly comprising an excavation tooth member and a lock as disclosed above with reference to any one of the above aspects of the disclosure.

The tooth member may be a tooth member as disclosed above with reference to any one of the aspect of the disclosure.

The excavation tooth assemblies may also comprise a further excavation tooth member.

According to a further aspect of the disclosure, there is provided a method of assembling a first tooth member and a second tooth member in an excavation tooth assembly, the method comprising:

coupling the first tooth member to the second member by receiving a nose portion of the second tooth member in a socket of the first tooth member;

inserting a lock into a locking space formed by the first and second tooth members; and

engaging inter-engaging elements disposed on the lock and one or both of the first and second tooth members to releaseably retain the lock within the locking space in an operative position where it locks the first tooth member to the second tooth member.

According to a further aspect of the disclosure, there is provided a method of assembling a first tooth member and a second tooth member in an excavation tooth assembly, the method comprising:

coupling the first tooth member to the second member by receiving a nose portion of the second tooth member in a socket of the first tooth member;

inserting a lock into a locking space formed by the first and second tooth members; and

receiving a detent disposed on a surface of the first or second tooth member in a recess of the lock to releaseably retain the lock within the locking space in an operative position where it locks the first tooth member to the second tooth member.

Brief Description of the Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of an excavation tooth assembly according to an comprising an excavation tooth point, an excavation tooth adapter and a lock;

Figure 2 is a perspective view of the excavation tooth assembly of Figure 1 showing the lock being inserted in a space between the point and the adapter to lock the point to the adapter;

Figure 3 is a perspective and side view of the lock of Figure 1 ;

Figure 4 is an exploded view of the lock of Figure 1 ;

Figure 5 is a rear end view of the point of Figure 1 with the lock in the position where it would lock the point to the adapter and showing the detent received in the recess;

Figures 6 and 7 are exploded perspective views of an excavation tooth assembly according to another embodiment;

Figures 8 and 9 are rear and top views respectively of the assembled excavation tooth assembly of Figure 6;

Figures 10, 1 1 and 12 are side, perspective and exploded views of a lock of the excavation tooth assembly of Figure 6; and

Figures 13 and 14 are a plan view and a cross-sectional plan view respectively of the point and adapter of the excavation tooth assembly of Figure 6. Detailed Description of Embodiments

Referring to Figures 1-5, there is shown an excavation tooth assembly 10 according to an embodiment which can be assembled to form an excavation tooth. The assembly 10 comprises an excavation tooth adapter 1 1 for mounting the excavation tooth to the digging edge of digging equipment, an excavation tooth point 12 for coupling to the adapter 1 1 and a lock 13 for locking the point 12 to the adapter 1 1 to form the excavation tooth.

The adapter 1 1 is a conventional excavation tooth adapter and comprises a forward projecting nose 20 and rearward arms 21 , 22. The rearward arms 21 , 22 are positioned either side of the digging edge of digging equipment in order to mount the adapter 1 1 thereto. The forward projecting nose 20 has a conventional 'twisted' shape to reduce the torsion stresses on the adapter in use. Ledges 24 are also provided on either side of the adapter between the nose 20 and the rearward arms. The purpose of these ledges will become apparent further on in the specification.

The point 12 comprises adigging edge 30 at a first end which engages the ground in use and a socket 31 at an opposite second end for receiving the nose 20 of the adapter 1 1 . The socket 31 has an internal 'twisted' shape, which conforms with the shape of the adapter nose 20. The point 12 is thus coupled to the adapter 1 1 by positioning the socket 31 at the end of the nose 20 and then twisting and pushing the point 12 until the nose 20 is received in the socket. Ears 32, 33 on either side of the point 12 extend rearwardly of the socket 31 , providing surfaces that face laterally relative to the first and second ends of the point. Each ear 32, 33 has upper and lower lugs 34-37 extending inwardly at the distal end of their respective ears 32, 33. When the point 12 is coupled to the adapter 1 1 with the adapter nose 1 1 fully received in the point socket 31 , the lugs 34-37 are located behind the adapter ledges 24 relative to the socket 31. In this arrangement, the ears 32, 33, the lugs 34-37 and the ledges 24 create locking spaces 80 on either side of the excavation tooth into which the lock 13 can be inserted to lock the point to the adapter in an operative position.

The point 12 also comprises a detent 38 for being received in a recess of the lock 13 to lock the point to the adapter. The detent 38 and the recess form a lock assembly and when coupled act to releaseably retain the lock within the locking space. The detent 38 has a general trapezoidal prism shape and is a projection which is elongate in the longitudinal direction of the point 12. However, the detent may be of any other suitable shape such as cylindrical or rectangular prism for example. The detent 38 is located on and protrudes inwardly from the laterally facing surface of one of the ears 32 at an intermediate portion of the ear 32 located vertically between the lugs 34, 35. A further detent (not shown) is provided on the other ear 33. This further detent is identical to the detent 38 shown and is located at an identical position on the other ear 33 to the location of the detent 38 on the ear 32. This enables the point 12 to be coupled and locked to the adapter 1 1 in an upside down orientation to that shown in Figures 1 -5. This is particularly useful in extending the life of the point 12 if the digging edge 30, in use, is wearing more on the top or bottom. A lug 34,37 on each wall may be provided with an lug recess 39 for co-operating with a different type of lock to the lock 13 described below.

Referring in particular to Figures 3 and 4, the lock 13 comprises a body 40 in the form of a unitary metal (eg. steel) casing. The lock 13 also comprises a recess 41 for receiving the detent 38 of the point 12 to releaseably retain the lock within the locking space

80. The recess 41 shown in Figures 1-5 is in the form of an elongate slot. However, other suitable types of recesses may be employed such as circular or rectangular indentations or through holes. The lock 13 is inserted between the point 12 and the adapter 1 1 after they have been coupled together by hammering the lock 13 (or otherwise applying a sufficient force to the lock) into one of the locking spaces 80 until the detent on the relevant point ear

32, 33 is received in the lock recess 41. To remove the lock 13, a further force is applied in the same direction as was applied during insertion which is sufficient for the detent to clear the recess.

Although the embodiment shown and described in the Figures has the detent formed on a surface of the point, the detent may instead be formed on a surface of the adapter.

The body 40 of the lock 13 is elongate and slightly curved in its longitudinal direction such that it is slightly convex at its front 42 and slightly concave at its rear 43. Nominal descriptions of 'front' and 'rear' have been provided of the lock body 40 which conform with the orientation of the lock 13 with respect to the point 12 when it is inserted into the locking space between the point and the adapter 1 1 (see Figures 1 and 2).

The body 40 has a compartment 44 for receiving a resilient insert 45 located in an intermediate portion of the body 40. For the lock 13 to be used, it is noted that the body 40 and insert 45 must be assembled with the insert received in the compartment 45. The compartment 44 has openings 46, 47 for portions of the insert 45 to protrude from when the insert 45 is received in the compartment 44. One of the openings 46 is located in the side of the body 40 and the other opening 47 is located at the front 42 of the body 40.

The insert 44 comprises a unitary elastomeric block 48 and two bearing members

49, 50, which are angularly spaced from one another by aproximatel 90°. The elastomeric block 48 allows the lock 13 to be deformedin order to insert (and remove) the lock 13 between the point 12 and the adapter 1 1. In particular, the elastomeric block allows the bearing members 49, 50 to be pressed in from an extended position to a retracted position as the lock is inserted (and removed). The elastomeric block 48 also biases the lock 13, specifically the bearing members 49, 50, towards its at rest shape.

Although the lock shown in Figures 1-5 has a single insert comprising a unitary elastomeric block it is to be understood that the insert may comprise multiple elastomeric blocks or that the lock may comprise more than one insert each comprising one or more elastomeric blocks. For example, the first bearing member may be mounted to a first elastomeric block and the second bearing member may be mounted to a second elastomeric block.

However, advantageously, the embodiment shown in the Figures having a unitary elastomeric block in a single compartment of the lock body is easier and more cost effective to manufacture. In particular, this is because the casting of the lock body with the single elastomeric block is easier to cast.

The bearing members 49, 50 are typically formed of metal such as steel. The bearing members may be formed as separate members and individually bonded to the elastomeric block 48 or they may be formed as a unitary element (which is bonded to the elastomeric block). The first bearing member 49 is located on a front face of the elastomeric block 48 and protrudes from the front opening 47 of the compartment 44. The first bearing member 49 provides an adapter bearing face 51 for bearing against the adapter 1 1 when the lock is in its operative position and locking the point to the adapter. More specifically, the adapter bearing face 51 is for bearing against one of the adapter ledges 24. The adapter bearing face 51 also aids in the locking of the point 12 to the adapter 1 1 by acting against vertical forces of rotation on the point 12.

The rear 43 of the lock body bears against one of the pairs of lugs (34 and 35 for example) when the lock is in its operative position and locking the point to the adapter. This bearing of the lock body rear 43 provides a opposing force to the adapter bearing face 51. Notably, because the adapter bearing face 51 is mounted to the elastomeric block 48, the lock self tightens as it or the adapter wears. This is because the elastomeric block pushes the adapter bearing face 51 outwards from the lock.

The second bearing member 50 is located on a side face of the elastomeric block

48 and protrudes from the side opening 46 of the compartment 44. The second bearing member 50 has the recess 41 of the lock 13 formed therein. Because of the position of the compartment 44 in the body 40, the recess 41 is located at an intermediate portion of the lock 13. The recess 41 is in the form of an elongate slot, which is elongate in a direction which is transverse to the longitudinal extent of the lock body 40. The dimensions of the recess 41 ensure that the detent 38 of the point resides firmly in the recess 41 once received therein (ie. the detent 38 is not free to move around in the recess 41 ) to avoid the lock slipping after it has been inserted into its locking position.

The lock 13 also comprises a shoulder element 52 which is formed on the second bearing member 50 for aiding the lock in passing over the detent as the lock is inserted into the locking space before the detent is captured in the recess. The shoulder element 52 provides a sloping bearing face 53 or ramp which rises towards the detent entry side of the recess. When the lock is inserted between the point and the adapter, the sloping bearing face 53 engages and travels over the detent 38 with increasing force on the shoulder element 52 towards the lock 13. Compression of the underlying elastomeric block 48 occurs under this force allowing the shoulder element 52 to gradually clear the detent 38. Once the lock has been sufficiently inserted to align the recess 41 with the detent 38, the bias of the elastomeric block 48 pushes the recess 41 towards the detent 38 so that the detent is received therein. It is noted that the second bearing member 50 has a further shoulder element formed on the other side of the recess 41 whereby the shoulder elements define the sides of the recess.

The insert 45 also comprises tabs 54 at its top and bottom for keying into depressions 55 at the top and bottom of the compartment 44 to lock the insert 45 into the compartment (see Figure 4). The insert 45 is received in the compartment 44 through the front opening 47. During this process, the tabs 54 deflect into the insert 45 as angled engaging surfaces 56 of the tabs 54 initially engage the top and bottom of the compartment respectively. This enables the insert 44 to clear the opening 47. However, the tabs 54 are biased towards their at rest position and thus once they align with the depressions 55 move outwardly to be received therein to lock the insert in the compartment. It is to be understood that the insert 45 may comprise mechanisms other than the tabs for securing the insert 45 in the compartment 44. For example, the tabs could be formed on the lock body and the depressions formed in the insert or a chemical bond may be formed between the insert and the body 40. In another arrangement, the insert may have a ledge which abuts a lip of the compartment once the insert has been positioned in the compartment. In this arrangement, the abutment of the ledge on the lip prevents the insert from inadvertently coming out of the compartment.

The lock 13 also comprises a groove 60 for enabling the lock to clear the detent 38 when inserting the lock into and removing the lock from the locking space between the adapter and the point. Accordingly, the width and depth of the groove along its length is approximately equal to or slightly greater than the width and height of the detent 38. The groove 60 is formed in a side of and extends the length of the lock body 40. The groove 60 is slightly curved with the curvature of the lock body 40. The groove 60 comprises first and second groove portions 61 , 62 either side of the recess 41 (and either side of the side opening 46 of the compartment 44). The first groove portion 61 widens at its distal end 63 from the recess 41 . The distal end of the first groove portion is at the leading edge of the lock 13 as it is inserted. The wider distal end 63 thus helps locate the detent 38 into the groove 60 as the lock is inserted. The second groove portion 62 widens at its proximal end 64 to the recess 41. The wider proximal end 64 similarly helps locate the detent 38 into the groove 60 when the lock is being removed and the recess is pushed over the detent 38.

The resilient insert 45 and in particular the second bearing member 50

incorporating the recess 41 is disposed in the lock body so as to be in general alignment with the groove 60. It is the insert 45 that interrupts the groove so as to separate the groove into the first and second groove portions. The insert 45 is set into the groove of the lock body so that when the recess is in an extended position, second bearing member 50 and in particular the shoulder elements defining the recess are disposed at or below the outer periphery of the lock body. When the recess moves to its retracted position, the insert moves further into the groove so that the shoulder elements drop further below the outer periphery of the lock body.

The lock 13 also comprises a ridge 70 extending from the rear 43 of the lock body 40 for engaging the ears 34-37 on one of the point walls 32, 33. The ridge 70 acts as a key to prevent the lock 13 being inserted into the space between the point 12 and the adapter 1 1 in the wrong orientation in which it could possibly get jammed.

Referring now to Figures 6-14, an excavation tooth assembly 1 10 according to another embodiment of the present invention is shown. The assembly 1 10 has similar features to the excavation tooth assembly 10 shown in Figures 1-5. Such features have been given the same reference number but have been prefixed with the numeral 1.

The assembly 1 10 comprises an adapter 1 1 1 , a point 1 12 and a lock 1 13. The adapter 1 1 1 has a nose portion 120 and the point 1 12 comprises a body having a first digging end and an opposite second end which incorporates a socket 131 in which the nose portion of the adapter is received. The lock 1 13 locks the point to the adapter. An important additional feature of the excavation tooth assembly 1 10 of Figures 6- 12 are the upper and lower ridges, 170 and 171 respectively, which are formed on the rear surface 173 of the point 1 12. The rear surface 173 of the point 1 12 is provided at the second end of the point body. The ridges 170, 171 are formed above and below the socket 131 (which opens in the rear surface 173) and are spaced from the rearwardly extending ears 132, 133. The ridges 170, 171 extend laterally across the rear surface 173 of the point and are concave in shape with thicker end portions 174a-d. The side surfaces of the end portions 174a-d form opposing surfaces with their respective opposing ears 132, 133. These opposing surfaces together with the rear surface 173 form locking spaces 180 with the adapter nose 120 into which the lock 1 13 can be inserted to lock the point 1 12 to the adapter 1 1 1. The opposing surfaces extend from a rear portion of the point (at the second end of the point body) towards the front of the point, which is at the first digging end of the point body.

The provision of the ridges 170, 171 , in particular their end portions 174a-d, constrains the top and bottom of the lock 1 13 against lateral movement with respect to the point 1 12 once inserted into its operative position in the locking space 180. This ensures that the recess 141 of the lock 1 13 remains engaged with the detent 138 on the point when the parts of the assembly 10 become worn through use. In particular, the ridges advantageously enable the excavation tooth assembly to incorporate adaptors with very worn nose portions because the lock is held in the locking space without any involvement from a surface of the adaptor.

In another variation not shown in the Figures, the upper and lower ridges may be replaced with protrusions which extend from the rear surface 173 at a location near to but spaced from the rearwardly extending ears 132, 133. Such protrusions form opposing surfaces with respective ears and provide the function of the end portions 174a-d of the ridges to constrain the top and bottom of the lock against lateral movement with respect to the point.

In a further variation, at least one indentation is provided at the second end of the point body which defines the opposing surfaces. In this embodiment, each indentation extends from a rear portion of the point towards the front of the point.

Another variation in the excavation tooth assembly 1 10 shown in Figures 6-12 over the assembly 10 of Figures 1 -5 is the that detent 138 on the point in a direction transverse to the longitudinal direction of the point 1 12. Accordingly the associated recess 141 of the lock 1 13 is elongate in the longitudinal direction of the lock.

Advantageously, the excavation tooth assembly of the embodiments described above is easier to assemble and disassemble than prior tooth assemblies. In particular, the lock is easier to install and remove from the locking space. A significant reason for this is the provision of the groove 60 in the lock body which runs over the detent 38 as the lock is being inserted or removed from the locking space. The groove acts to guide the direction of the lock as it is being moved. This means that under the repeated percussive forces of hammering the lock into and out of the locking space, it is not driven in an incorrect angle and jammed. Furthermore, for the removal process, any fines which have collected in the groove during use are pushed out by the detent as the groove travels over it.

It is to be understood that, unless indicated otherwise by express language or necessary implication, the tooth members or locking members according to any embodiment of one aspect of the present invention may further encompasses any one or combination of features described above in relation to embodiments of other aspects of the present invention.

It is also to be understood that whilst the above description has been made in respect of a two part excavation tooth assembly (adaptor and point), the embodiments of the present invention described above may be incorporated into a three part excavation tooth assembly comprising an adaptor, a point and an intermediate member disposed between and coupling to each of the adaptor and the point. The intermediate member may have some of the features described above for the point and some of the features described above for the adaptor.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.