Attachment of a Heel Shroud

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.

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.

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

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

The projection is preferably cylindrical or part-cylindrical.

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.

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.

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

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.

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.

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.

The heel shroud may be generally L-shaped, having a sidewall-abutting 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.

The sidewall-abutting portion has a sidewall-abutting face. The floor-abutting portion has a floor-abutting face.

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 floor-abutting portion arranged to locate, in use, about an inner region of a boss fixed to the bucket sidewall.

The floor-abutting face is preferably perpendicular to the sidewall-abutting 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.

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.

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.

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

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.

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.

Referring to the Figures,shows a portion of a bucket heelof an excavator bucket, representing a portion of a bucket floorand a bucket sidewall. A heel shroudis shown attached to the bucket heel.

The bucket heelis shown from a different perspective, without the heel shroud, in. The bucket heelincludes two bosses welded to outer faces thereof: a sidewall bosswelded to the sidewalland a floor bosswelded to the bucket floor.

The sidewall bosshas a relatively shallow outer portionand a deeper inner portion. An outer faceof the sidewall bosstapers from the outer portionto the inner portion. The inner portionhas an edgewhich is arranged to locate along an edge of the sidewall; that is, along the border between the sidewalland the bucket floor.

The inner portionhas two tail portionswhich extend away from the edge. The two tail portionsare spaced at opposite lateral ends of the inner portion.

The sidewall bossis shown from a reverse side in. The sidewall bosshas generally planar inner facewhich is arranged to abut against and be contiguous with the sidewall.

The outer portioncomprises two side portionsdivided by a restraining means receiving cavity. The inner faceincludes two locating arm receiving recesses, one located on either side of the restraining means receiving cavity. Each locating arm receiving recessextends from an outer edge of the sidewall bossthrough about half of a length of the outer portion. Each locating arm receiving recessis formed by a reduction in the thickness of the outer portion, creating a stepped region of the inner facesuch that the locating arm receiving recesslocates, in use, between the stepped region of the inner faceand the bucket sidewall. Each locating arm receiving recessincludes a resilient locator receiving cavity formed by an indentalongside the restraining means receiving cavityclose to the outer edge of the sidewall boss.

The inner portionincludes a laterally extending locking-arm receiving recesswhich extends from a base of the restraining means receiving cavityto a position close to the edge. The locking-arm receiving recessis formed in a similar manner to the locating arm receiving recesses. The locking-arm receiving recesshas an outer lipwhich forms a base of the restraining means receiving cavity.

The floor bossis formed from two railswhich are joined at an outer endto form a U-shape. The floor bosshas a flat lower surfacewhich is parallel to a flat upper surfaceof narrower width. Each railhas an outer side wallhaving two portions: a first portionwhich is perpendicular to the lower surfaceand a second portionangled at about 45° with respect to the first portion. The first portionextends about 75% of the distance between the lower surfaceand the upper surface.

An inner side wallof the floor bosshas four portions: a first portionremote from the outer end, the first portionbeing parallel to the outer side wall; a second portioninwardly spaced relative to the first portion, the second portionbeing angled at about 60° relative to the lower surfacesuch that the upper surfacealongside the second portionhas the same width as the upper surfacealongside the first portion; a third portionparallel to the first portionand being inwardly spaced relative to the first portionsuch that the lower surfacealongside the third portionhas a slightly greater width than the lower surfacealongside the second portion; and a fourth portionparallel to the second portion, with the upper surfacealongside the fourth portionhaving the same width as the upper surfacealongside the third portion.

It will be appreciated that this forms railshaving a stepped configuration.

The flat upper surfaceis arranged to abut against and be contiguous with the bucket floor. The railsare arranged such that their inner ends locate within the tail portionsof the sidewall boss. As can be seen inthe inner end of each railscan be welded to both a tail portionof the sidewall bossand to the lower edge.

The heel shroudis shown in. The heel shroudis broadly L-shaped in cross section, with a sidewall-abutting portiongenerally perpendicular to a floor-abutting portion. The sidewall-abutting portionhas an outer wear faceand an inner sidewall-abutting face. The floor-abutting portionhas an outer wear faceand an inner floor-abutting face.

The floor-abutting faceis at two levels: an upper leveland a stepped lower level. The upper levelis arranged, in use, to seat against the floorof the bucket heel. The lower levelis arranged, in use, to seat against the lower surfaceof the rails.

The floor-abutting facehas two side portionsat the upper level, and an inner islandalso at the upper level. The effect is to create two channelsat the lower level, each channel extending between a side portionand the inner island.

The inner islandhas two side walls. The side wallsare complementary in shape to the inner side wallsof the floor boss; that is, the side wallshave a stepped configuration with alternating angled and perpendicular portions.

The arrangement is such that the heel shroudcan be positioned at the edge of the bucket heeland then slid in a horizontal direction with the railsengaged within the channels. This can continue until the inner islandmeets the outer endof the rails, at which time the sidewall-abutting facewill be located against the bucket sidewall.

The sidewall-abutting portionhas an outer edge. A lock receiving cavityextends in a channel centrally of the sidewall-abutting portionfrom the outer edge, representing about one quarter of the lateral extent of the sidewall-abutting portion. The lock receiving cavityextends about halfway along the sidewall-abutting portionin a direction towards the floor-abutting portion.

The sidewall-abutting faceincludes generally flat forward locating surfacesalong each lateral side of the sidewall-abutting portion. The arrangement is that, in use, the forward locating surfacesbear against the bucket sidewall.

The sidewall-abutting facealso includes generally flat rearwardly spaced locating surfacesalong each lateral side of the lock receiving cavity. The rearwardly spaced locating surfacesare arranged to bear against the outer portionof the sidewall boss.

The sidewall-abutting facehas a tapered regionlocated beneath the lock receiving cavity. The tapered regionextends laterally across the sidewall-abutting facebetween the two forward locating surfaces. The tapered regionis complementary in shape to the inner portionof the sidewall boss, including the tapered portion of the outer face.