“ATTACHMENT OF A HEEL SHROUD”

Field of the Invention

[0001 ] The present invention relates to a locking assembly for attachment of ground engaging tools to earthmoving equipment. The present invention has been designed for the attachment of a heel shroud to an excavator bucket, but may have wider application in the attachment of ground engaging tools.

Background to the Invention

[0002] Buckets of excavating equipment are subject to significant abrasive wear during use. For this reason, replaceable ground engaging tools (GET) are located about the buckets in the areas most susceptible to wear. A number of different GET are used, including wing shrouds, heel shrouds, lip shrouds, adaptors, wear plates, teeth and corner shrouds.

[0003] The efficient connection of shrouds such as heel shrouds to excavator buckets has long presented a challenge.

[0004] Broadly speaking, GET are attached in one of two ways: by welding or by mechanical engagement. Welding creates a stronger connection, but makes removal and replacement of the GET difficult. Mechanical engagement, often via pinned systems, represents a significantly more complex arrangement which may not be as secure.

[0005] In general, mechanical engagement is useful for relatively small forces (or smaller GET components). Heel shrouds are usually connected by welding as it is difficult to design a sufficiently simple, small and robust locking system which provides effective wear protection.

[0006] When a welded heel shroud requires replacement, it must be cut from a bucket; the surfaces must be smoothed; and then a new heel shroud must be welded in place. This requires significant down-time during which the bucket cannot be used. Mechanical systems, on the other hand, generally allow much faster replacement and thus less down-time. [0007] In recent years some manufacturers of GET have been offering bolted heel shrouds as an alternative to welding. Bolted shrouds require the use of a bolt passing through the bucket heel. This has the effect of potentially weakening the bucket heel, and also requires access to the bolt from within the bucket. Further, bolts are subject to bending under load which can make their removal problematic.

[0008] The present invention proposes a mechanical engagement for connection of GET which addresses these issues.

Summary of the Invention

[0009] According to one aspect of the present invention there is provided a heel shroud assembly for connection to an excavator bucket, the heel shroud assembly including a heel shroud, a locking arm, and a restraining means, whereby the locking arm is arranged to pivot about an axis of the heel shroud, and the restraining means is arranged to selectively restrict the pivoting of the locking arm. Each of the heel shroud, the locking arm, and the restraining means constitutes a further separate aspect of the invention.

[0010] The locking arm may include a bucket engaging portion and a projection. It is preferred that the bucket engaging portion and the projection extend on opposite sides of the axis.

[0011 ] The bucket engaging portion may be generally prismatic in shape. In a preferred embodiment, the bucket engaging portion may have a generally convex outer surface arranged, in use, to contact a bucket sidewall; and a generally inner concave surface arranged, in use, to contact a boss fixed to the bucket sidewall. The bucket engaging portion may be tapered; that is, the outer surface may have a larger radius of curvature than the inner surface. The bucket engaging portion may have a nose portion in which the outer surface and the inner surface are parallel to each other. [0012] The bucket engaging portion may include an axial bore through which an axle is arranged to pass. Preferably the bucket engaging portion is arranged to pivot about the axle.

[0013] The heel shroud preferably includes a cylindrical bearing aperture extending in the axial direction on either side of the locking arm. In a preferred embodiment the axle is located within the cylindrical bearing aperture.

[0014] The axle may be internally threaded at either end, so as to receive an externally threaded cap screw at either end. In a preferred embodiment a locating member may be held in position by each cap screw. The locating member may be partially frusto-conical.

[0015] The projection is preferably cylindrical or part-cylindrical.

[0016] The restraining means may have a central body portion, a tail portion extending from the central body portion in a generally axial direction, and locating arms extending laterally of the central body portion.

[0017] The locating arms preferably extend from a front face of the central body portion. The tail portion preferably extends from a rear face of the central body portion.

[0018] The restraining means may have a resilient locator positioned within at least one of the locating arms.

[0019] At least one of the locating arms may include a notched portion towards an outer end thereof, the notched portion being arranged to receive an end of a pry tool.

[0020] The restraining means may have a bore arranged to receive the projection of the locking arm. The bore may extend in a generally axial direction through the central body portion. In a preferred embodiment, the bore is generally stadium shaped in cross section, with a width in the lateral direction less than a length in a forward direction. [0021 ] The restraining means may include a tightening member arranged to extend into the bore. In a preferred embodiment, the tightening member is located in an aperture extending between a rear surface of the central body portion and the bore. The aperture is preferably threaded. The tightening member may be a grub screw.

[0022] The heel shroud may be generally L-shaped, having a sidewallabutting portion generally perpendicular to a floor-abutting portion. The sidewall-abutting portion preferably includes a lock receiving cavity. In a preferred embodiment the lock receiving cavity extends in a channel generally centrally of the sidewall-abutting portion, from an outer edge remote from the floor-abutting portion towards the floor-abutting portion. The cylindrical bearing aperture passes through the lock receiving cavity.

[0023] The sidewall-abutting portion has a sidewall-abutting face. The floorabutting portion has a floor-abutting face.

[0024] The sidewall-abutting face may include forwardly locating surfaces along outer lateral sides of the sidewall-abutting face arranged to locate, in use, against a bucket sidewall; rearwardly spaced locating surfaces alongside the lock receiving cavity arranged to locate, in use, against an outer portion of a boss fixed to the bucket sidewall; and a tapered region adjacent the floorabutting portion arranged to locate, in use, about an inner region of a boss fixed to the bucket sidewall.

[0025] The floor-abutting face is preferably perpendicular to the sidewallabutting face. The floor-abutting face preferably includes at least two channels arranged to receive locating rails. Each channel may be of a stepped configuration, with a narrower end towards the sidewall-abutting portion and a wider end remote from the sidewall-abutting portion. In a preferred embodiment, each channel includes three or four widening steps. In alternative embodiments the channels may be of constant width or may taper along their length. [0026] According to a further aspect of the present invention there is provided an excavator bucket arranged to receive a heel shroud, the excavator bucket including a sidewall boss fixed to a sidewall of the excavator bucket and a floor boss fixed to a floor of the excavator, the sidewall boss and the floor boss combining to form an attachment location for a heel shroud, wherein the floor boss includes locating rails arranged to receive a floor-abutting face of a heel shroud and the sidewall boss includes a locking-arm receiving recess arranged to receive a bucket engaging portion of a locking arm associated with the heel shroud.

[0027] Preferably the floor boss is generally U-shaped. In a preferred embodiment each locating rail is a of a stepped configuration, with the width of each locating rail narrowing away from the U-shaped bend.

[0028] The locking-arm receiving recess of the sidewall boss may extend from a restraining means receiving cavity in a direction towards the excavator floor.

[0029] The sidewall boss may include a locating arm receiving recess alongside at least one side of the restraining means receiving cavity, the locating arm receiving recess facing the excavator sidewall. The locating arm recess may include a resilient locator receiving cavity.

[0030] The sidewall boss may include a relatively shallow outer portion remote from the floor boss and a relatively deeper inner portion arranged to abut the floor boss.

Brief Description of the Drawings

[0031 ] It will be convenient to further describe the invention with reference to preferred embodiments of the present invention. Other embodiments are possible, and consequently the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings: [0032] Figure 1 is a perspective of a portion of an excavator bucket heel shown with a heel shroud attached in accordance with the present invention;

[0033] Figure 2 is a lower perspective of the portion of the excavator bucket heel of Figure 1 , shown without the heel shroud;

[0034] Figure 3 is an exploded view of the portion of the excavator bucket heel of Figure 2, showing a sidewall boss and a floor boss before attachment to the bucket heel;

[0035] Figure 4 is a perspective from a reverse side of the sidewall boss of Figure 3;

[0036] Figure 5 is an under view of the floor boss of Figure 3;

[0037] Figure 6 is a front perspective of the heel shroud of Figure 1 ;

[0038] Figure 7 is a rear perspective of the heel shroud of Figure 6;

[0039] Figure 8 is a rear view of the heel shroud of Figure 6;

[0040] Figure 9 is a partially cut-away front perspective of the heel shroud of Figure 6;

[0041 ] Figure 10 is a partially cut-away front view of the heel shroud of Figure 6;

[0042] Figure 11 is an exploded view of a locking arm assembly from within the heel shroud of Figure 1 ;

[0043] Figure 12 is a front view of the locking arm assembly of Figure 11 ;

[0044] Figure 13 is a rear view of the locking arm assembly of Figure 11 ; [0045] Figure 14 is an exploded view of the locking arm assembly of Figure 11 prior to insertion into the heel shroud of Figure 6;

[0046] Figure 15 is an exploded view of the locking arm assembly of Figure 11 during insertion into the heel shroud of Figure 6;

[0047] Figure 16 is a rear perspective of the heel shroud of Figure 6 into which the locking arm assembly of Figure 11 has been inserted;

[0048] Figure 17 is a partially cut-away front view of the heel shroud of Figure 6 following insertion of the locking arm assembly of Figure 11 ;

[0049] Figure 18 is a front view of a restraining means from within the heel shroud of Figure 1 ;

[0050] Figure 19 is an upper rear view of the restraining means of Figure 18;

[0051 ] Figure 20 is a lower rear view of the restraining means of Figure 18;

[0052] Figure 21 is an exploded view of the restraining means of Figure 18;

[0053] Figure 22 is an exploded view of a resilient locator from within the restraining means of Figure 18;

[0054] Figure 23 is an exploded view of the heel shroud assembly of Figure 1 immediately prior to attachment;

[0055] Figure 24 is a perspective of the heel shroud of Figure 6 being brought towards the excavator bucket heel of Figure 2;

[0056] Figure 25 is a sectional view of the heel shroud assembly of Figure 1 during attachment, showing engagement of the floor boss of Figure 3;

[0057] Figures 26 to 31 are sequential cross-sectional views through the heel shroud assembly of Figure 1 during attachment; [0058] Figure 32 is a front view of the heel shroud assembly of Figure 1 following engagement of the locking arm;

[0059] Figure 33 is an overhead view of the heel assembly of Figure 1 following engagement of the locking arm;

[0060] Figure 34 is a perspective of the restraining means of Figure 18 being brought towards the heel shroud assembly of Figure 1 following engagement of the locking arm;

[0061 ] Figure 35 is a cross-section through a portion of the heel shroud assembly during initial positioning of the restraining means of Figure 18;

[0062] Figure 36 is a cross-section through a portion of the heel shroud assembly following initial positioning of the restraining means of Figure 18;

[0063] Figures 37 to 39 are sequential cross-sectional views through the heel shroud assembly of Figure 1 during tightening; and

[0064] Figures 40 and 41 are perspectives of the heel shroud assembly of Figure 1 preparing for removal of the heel shroud.

Detailed Description of Preferred Embodiments

[0065] Referring to the Figures, Figure 1 shows a portion of a bucket heel 10 of an excavator bucket, representing a portion of a bucket floor 12 and a bucket sidewall 14. A heel shroud 80 is shown attached to the bucket heel 10.

[0066] The bucket heel 10 is shown from a different perspective, without the heel shroud 80, in Figure 2. The bucket heel 10 includes two bosses welded to outer faces thereof: a sidewall boss 16 welded to the sidewall 14 and a floor boss 18 welded to the bucket floor 12.

[0067] The sidewall boss 16 has a relatively shallow outer portion 20 and a deeper inner portion 22. An outer face 24 of the sidewall boss 16 tapers from the outer portion 20 to the inner portion 22. The inner portion 22 has an edge 26 which is arranged to locate along an edge of the sidewall 14; that is, along the border between the sidewall 1 and the bucket floor 12.

[0068] The inner portion 22 has two tail portions 28 which extend away from the edge 26. The two tail portions 28 are spaced at opposite lateral ends of the inner portion 22.

[0069] The sidewall boss 16 is shown from a reverse side in Figure 4.The sidewall boss 16 has generally planar inner face 30 which is arranged to abut against and be contiguous with the sidewall 14.

[0070] The outer portion 20 comprises two side portions 32 divided by a restraining means receiving cavity 34. The inner face 30 includes two locating arm receiving recesses 36, one located on either side of the restraining means receiving cavity 34. Each locating arm receiving recess 36 extends from an outer edge of the sidewall boss 16 through about half of a length of the outer portion 20. Each locating arm receiving recess 36 is formed by a reduction in the thickness of the outer portion 20, creating a stepped region of the inner face 30 such that the locating arm receiving recess 36 locates, in use, between the stepped region of the inner face 30 and the bucket sidewall 14. Each locating arm receiving recess 36 includes a resilient locator receiving cavity formed by an indent 38 alongside the restraining means receiving cavity 34 close to the outer edge of the sidewall boss 16.

[0071 ] The inner portion 22 includes a laterally extending locking-arm receiving recess 40 which extends from a base of the restraining means receiving cavity 34 to a position close to the edge 26. The locking-arm receiving recess 40 is formed in a sim ilar manner to the locating arm receiving recesses 36. The locking-arm receiving recess 40 has an outer lip 42 which forms a base of the restraining means receiving cavity 34.

[0072] The floor boss 18 is formed from two rails 50 which are joined at an outer end 52 to form a U-shape. The floor boss 18 has a flat lower surface 54 which is parallel to a flat upper surface 56 of narrower width. Each rail 50 has an outer side wall 58 having two portions: a first portion 60 which is perpendicular to the lower surface 54 and a second portion 62 angled at about 45° with respect to the first portion 60. The first portion 60 extends about 75% of the distance between the lower surface 54 and the upper surface 56.

[0073] An inner side wall 64 of the floor boss 18 has four portions: a first portion 66 remote from the outer end 52, the first portion 66 being parallel to the outer side wall 58; a second portion 68 inwardly spaced relative to the first portion 66, the second portion 68 being angled at about 60° relative to the lower surface 54 such that the upper surface 56 alongside the second portion 68 has the same width as the upper surface 56 alongside the first portion 66; a third portion 70 parallel to the first portion 66 and being inwardly spaced relative to the first portion 66 such that the lower surface 54 alongside the third portion 70 has a slightly greater width than the lower surface 54 alongside the second portion 68; and a fourth portion 72 parallel to the second portion 68, with the upper surface 56 alongside the fourth portion 72 having the same width as the upper surface 56 alongside the third portion 70.

[0074] It will be appreciated that this forms rails 50 having a stepped configuration.

[0075] The flat upper surface 56 is arranged to abut against and be contiguous with the bucket floor 12. The rails 50 are arranged such that their inner ends locate within the tail portions 28 of the sidewall boss 16. As can be seen in Figure 2 the inner end of each rails 50 can be welded to both a tail portion 28 of the sidewall boss 16 and to the lower edge 26.

[0076] The heel shroud 80 is shown in Figures 6 to 8. The heel shroud 80 is broadly L-shaped in cross section, with a sidewall-abutting portion 82 generally perpendicular to a floor-abutting portion 84. The sidewall-abutting portion 82 has an outer wear face 86 and an inner sidewall-abutting face 88. The floor-abutting portion 84 has an outer wear face 90 and an inner floorabutting face 92. [0077] The floor-abutting face 92 is at two levels: an upper level 94 and a stepped lower level 96. The upper level 94 is arranged, in use, to seat against the floor 12 of the bucket heel 10. The lower level 96 is arranged, in use, to seat against the lower surface 54 of the rails 50.

[0078] The floor-abutting face 92 has two side portions 98 at the upper level 94, and an inner island 100 also at the upper level 94. The effect is to create two channels 102 at the lower level 96, each channel extending between a side portion 98 and the inner island 100.

[0079] The inner island 100 has two side walls 104. The side walls 104 are complementary in shape to the inner side walls 64 of the floor boss 18; that is, the side walls 104 have a stepped configuration with alternating angled and perpendicular portions.

[0080] The arrangement is such that the heel shroud 80 can be positioned at the edge of the bucket heel 10 and then slid in a horizontal direction with the rails 50 engaged within the channels 102. This can continue until the inner island 100 meets the outer end 52 of the rails 50, at which time the sidewallabutting face 88 will be located against the bucket sidewall 14.

[0081 ] The sidewall-abutting portion 82 has an outer edge 110. A lock receiving cavity 112 extends in a channel centrally of the sidewall-abutting portion 82 from the outer edge 110, representing about one quarter of the lateral extent of the sidewall-abutting portion 82. The lock receiving cavity 112 extends about halfway along the sidewall-abutting portion 82 in a direction towards the floor-abutting portion 84.

[0082] The sidewall-abutting face 88 includes generally flat forward locating surfaces 114 along each lateral side of the sidewall-abutting portion 82. The arrangement is that, in use, the forward locating surfaces 114 bear against the bucket sidewall 14. [0083] The sidewall-abutting face 88 also includes generally flat rearwardly spaced locating surfaces 116 along each lateral side of the lock receiving cavity 112. The rearwardly spaced locating surfaces 116 are arranged to bear against the outer portion 20 of the sidewall boss 16.

[0084] The sidewall-abutting face 88 has a tapered region 118 located beneath the lock receiving cavity 112. The tapered region 118 extends laterally across the sidewall-abutting face 88 between the two forward locating surfaces 114. The tapered region 118 is complementary in shape to the inner portion 22 of the sidewall boss 16, including the tapered portion of the outer face 24.

[0085] A lateral bore 120 extends through the sidewall-abutting portion 82. The lateral bore 120 is located immediately outside the innermost extent of the lock receiving cavity 112. The lateral bore 120 is most clearly shown in Figures 9 and 10.

[0086] The lateral bore 120 includes a cylindrical inner region 122 on either side of the lock receiving cavity 112, a tapered or frusto-conical intermediate region 124 and then a cylindrical outer region 126 which extends from the intermediate region 124 to a lateral edge of the sidewall-abutting portion 82. The outer region 126 has a diameter about twice that of the inner region 122. The outer region 126 opens at the lateral side edge of the sidewall-abutting portion 82 at a bore opening 128. The inner region 122 opens into the lock receiving cavity 112 at a circular opening 130.

[0087] The inner region 122 forms a cylindrical bearing aperture for the heel shroud 80.

[0088] The heel shroud 80 has a locking arm assembly 140 positioned therein. The locking arm assembly 140 is shown in Figures 11 to 13.

[0089] The locking arm assembly 140 is comprised of a locking arm 142, an axle 144, two frusto-conical locators 146 and two cap screws 148. [0090] The locking arm 142 is formed from a bucket engaging portion 150 and a projection 152. The bucket engaging portion 150 is generally prismatic. It has a generally bulbous upper portion 154 and a tapered lower portion 156. The tapered lower portion 156 is formed by a convex outer surface 158 and a convex inner surface 160. The inner surface 160 is more tightly curved than the outer surface 158, meaning that the taper is formed to one side of the bulbous upper portion 154. The tapered lower portion 156 ends in a nose portion 162, in which the outer surface 158 and the inner surface 160 are parallel to each other before being joined by a rounded end.

[0091 ] The bulbous upper portion 154 has an axial bore 164 through which the axle 144 is arranged to pass.

[0092] The projection 152 is part-cylindrical, with an axis perpendicular to the axle 144. The projection 152 has a diameter about one third of the width of the bucket engaging portion 150. It extends away from the bulbous upper portion 154 in a direction generally opposite to that of the tapered lower portion 156. The projection 152 has a flattened rear face 153, oriented in the same direction as the inner surface 160.

[0093] The axle 144 is internally threaded at either axial end. Each cap screw 148 has an externally threaded shaft 166 and a head 168. The externally threaded shaft 166 is arranged to be engaged within an internally threaded end of the axle 144.

[0094] Each frusto-conical locator 146 has a stepped internal bore, whereby the axle 144 can be received within a larger diameter bore 170 at the narrower end of the locator 146, and the shaft 166 of the cap screw 148 can be received in a smaller diameter bore 172 at the wider end of the locator 146. The arrangement is such that the cap screw 148 holds the locator 146 about an outer end of the axle 144 as shown in Figures 12 and 13.

[0095] Insertion of the locking arm assembly 140 into the heel shroud 80 is shown in Figures 14 to 17. [0096] The locking arm 142 is positioned in the lock receiving cavity 112 with the tapered lower portion 156 of the bucket engaging portion 150 located generally in the tapered region 118 and with the axial bore 164 of the locking arm 142 aligned with the lateral bore 120 of the sidewall-abutting portion 82. It will be appreciated that in this position the projection 152 is located within the lock receiving cavity 1 12, extending towards the outer edge 110 in a direction generally perpendicular to the floor-abutting face 92.

[0097] The axle 144 can then be introduced from a bore opening 128 at one side of the heel shroud 80, such that it passes through a first outer region 126, a first intermediate region 124, a first inner region 122, a first circular opening 130, the axial bore 164 of the locking arm 142, a second circular opening 130, a second inner region 122, a second intermediate region 124, and into a second outer region 126.

[0098] The locators 146 and cap screws 148 can then be introduced through respective bore openings 128 and located such that the locators 146 bear against the respective frusto-conical intermediate regions 124. The cap screws 148 are threaded into the axle 144 to secure the locking arm assembly 140 within the heel shroud 80.

[0099] The heel shroud 80 is arranged to be used along with a restraining means 180. The restraining means 180 can be seen in Figures 18 to 21.

[0100] The restraining means 180 has a central body portion 182 which is prismatic, with a lateral width corresponding to that of the lock receiving cavity 112 of the heel shroud 80, and a depth similar to that of the lock receiving cavity 112. The central body portion 182 has a front face 184 and a rear face 186.

[0101 ] The restraining means 180 has a tail portion 188 which extends away from the central body portion 182 in a generally axial direction. The tail portion 188 is located on a rear side of the restraining means 180; that is, it extends from the rear face 186. [0102] Locating arms 190 extend laterally of the front face 184 of the central body portion 182 on both sides. The locating arms 190 combine with the front face 184 to form a planar first bearing surface 192.

[0103] The locating arms 190 each have a rear surface 194. The rear surfaces 194 are parallel to the first bearing surface 192. The locating arms 190 are sized so as to locate with respective locating arm receiving recesses 36 of the sidewall boss 16.

[0104] Each locating arm 190 has a notched portion 196 towards an outer end thereof, the notched portion 196 extending inwardly from an outer lateral side.

[0105] A bore 200 extends through the central body portion 182 in an axial direction. The bore 200 is stadium shaped in cross section, with a lateral width slightly greater than the diameter of the projection 152 and a depth in the forward direction about three times its width.

[0106] Each locating arm 190 includes a receiving recess 202 for receipt of a resilient locator 204. The receiving recess 202 is located generally centrally of the rear surface 194.

[0107] A resilient locator 204 is shown in Figure 22. The resilient locator 204 is formed from two components, a rigid end cap 206 formed of a hard material such as steel, and a resilient body portion 208 formed of a compressible material such as rubber. The rigid end cap 206 is formed with a locating protrusion 210 arranged to be received within a complementary locating recess 212 of the resilient body portion 208.

[0108] The resilient locators 204 are positioned within the receiving recesses 202 such that the rigid end caps 206 protrude from the rear surfaces 194.

[0109] The central body portion 182 includes an internally threaded aperture 220 which extends in a forward direction between the rear face 186 and the bore 200. The internally threaded aperture 220 is arranged to receive a tightening member, being a grub screw 222.

[0110] Attachment of the heel shroud 80 to the bucket heel 10 will be described with reference to Figures 23 to 39.

[0111 ] The heel shroud 80 is provided with the locking arm assembly 140 installed in the position of Figure 16. Figure 23 shows the components used for attachment: the bucket heel 10, the heel shroud 80, and the restraining means 180.

[0112] The heel shroud 80 is brought to the bucket heel 10 in a forward direction; that is, in the direction of the floor-abutting portion 84. The channels 102 of the floor-abutting face 92 engage with the rails 50 of the floor boss 18. This engagement is shown in Figure 25.

[0113] The heel shroud 80 can then be slid along the rails 50 until the sidewall-abutting face 88 approaches the sidewall 14, as shown in Figure 26.

[0114] At this point, the locking arm 142 is rotated in the order of 70° about the axle 144, such that the bucket engaging portion 150 extends in a direction towards the sidewall 14 and the projection 152 extends rearwardly of the outer wear face 86. It is anticipated that a tool may be used to effect this rotation, such as an appropriately sized hollow pipe. This position is shown in Figure 27.

[0115] The heel shroud 80 is then slid further along the rails 50 such that the nose portion 162 of the locking arm 142 moves past the lip 42 of the sidewall boss 16 as shown in Figure 28.

[0116] The locking arm 142 can then be rotated back in the opposite direction until the inner surface 160 of the tapered lower portion 156 contacts the outer lip 42 of the sidewall boss 16 as shown in Figure 29. [0117] Further rotation of the locking arm 142 results in the inner surface 160 of the tapered lower portion 156 bearing against the locking arm receiving recess 40 of the sidewall boss 16, and actively pulling the shroud 80 onto the bucket heel 10 as shown in Figures 30 and 31 .

[0118] In this intermediate position the tapered lower portion 156 locates within the locking arm receiving recess 40, with the inner surface 160 bearing against the locking arm receiving recess 40 and the outer surface 158 bearing against the bucket sidewall 14. The sidewall-abutting face 88 of the shroud 80 is now located close to the bucket sidewall 14. The projection 152 is close to its original orientation; that is, it is parallel to the bucket sidewall 14. This intermediate position is shown in Figures 32 and 33.

[0119] The restraining means 180 is now introduced into the lock receiving cavity 112 as shown in Figure 34 in order to restrict rotation of the locking arm 142, and thus prevent disengagement of the shroud 80 from the bucket heel 10; as well as to tighten the arrangement into a final position.

[0120] The restraining means 180 is pushed into position such that the projection 152 enters the bore 200 and the locating arms 190 enter the locating arm receiving recesses 36 of the sidewall boss 16.

[0121 ] As the locating arms 190 are pushed into the locating arm receiving recesses 36, the resilient locators 204 are compressed as shown in Figure 35. When the restraining means 180 reaches its final position, the resilient locators 204 are positioned at a respective indent 38. This allows for expansion of each resilient locator 204, with the rigid end cap 206 bearing against the indent 38 as shown in Figure 36. This prevents accidental dislodgement of the restraining means 180.

[0122] When the restraining means 180 is thus positioned, the grub screw 222 can be operated to tighten the heel shroud 80 to the bucket heel 10. Advancing of the grub screw 222 as shown in Figures 37 to 39 provides a force against the flattened rear face 153 of the projection 152, acting as a moment about the axle 144 and causing rotation of the locking arm 142.

[0123] This further rotation causes the inner surface 160 to bear against the locking arm receiving recess 40 and further urge the heel shroud 80 onto the bucket heel 10. This can be seen in Figures 37 to 39 by the closing of the gap between the inner island 100 of the floor-abutting face 92 and the outer end 52 of the floor boss 18.

[0124] In the final position of Figure 39 the heel shroud 80 is tightly held against the bucket heel 10, with the projection 152 secured within the bore 200 by means of the grub screw 222.

[0125] Removal of the heel shroud 80 can be effected with use of a pry tool 230 as shown in Figures 40 and 41. The pry tool 230 can be inserted into a notched portion 196 of one of the locating arms 190 as shown in Figure 40, or between the edge of the tail portion 188 of the restraining means 180 and a base of the lock receiving cavity 112 of the heel shroud 80. The pry tool 230 is used to lever the restraining means 180 out of the lock receiving cavity 112, forcing the resilient locators 204 out of the indents 38. This can be achieved without the need to unscrew the grub screw 222.

[0126] Once the restraining means 180 has been removed using the pry tool 230, the projection 152 can be rotated such that the outer surface 158 of the tapered lower portion 156 pushes against the bucket sidewall 14, forcing release of the heel shroud 80 from the bucket heel 10.

[0127] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.