AU728936B3 - Improvements in adaptor parts for ground engaging elements - Google Patents

Description

P/00/009 Regulation 3.2 THE TRACK SHOP PTY LTD

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: "IMPROVEMENTS IN ADAPTOR PARTS FOR GROUND ENGAGING ELEMENTS" This invention is described in the following statement: in which at least the lower ground engaging face is capped with -1- "IMPROVEMENTS IN ADAPTOR PARTS FOR GROUND ENGAGING ELEMENTS" THIS INVENTION relates to improvements in adaptor parts for ground engaging elements.

The invention has particular application to adaptors for mounting ground engaging teeth to a drag-line bucket, and for illustrative purposes, reference will be made to such application. However, the invention may also have application to the adaptor parts for ground engaging elements of other earth moving machinery, such as mechanical shovels, back hoes or such like. Adaptors for mounting ground engaging teeth to dragline buckets are usually provided with a wear resistant hardfacing on at least the lower, ground engaging face to resist wear caused by the adaptor engaging the ground during digging, ditching, scraping, ripping or backfilling and the like. The hardfacing is typically a wear resistant material, such as tungsten carbide, dispersed in a weld matrix. The teeth are usually removably attached to the adaptor, and the adaptor in turn is removably attached to the bucket.

Typically, the adaptor has four converging faces providing a larger end attachable to a drag-line bucket and a smaller end to which a ground engaging element, such as a ground engaging tooth may be attached. Accordingly, each converging face is roughly trapezoidal, and such adaptors are sometimes referred to in the art as "trapezoidal adaptors".

The hardfacing forming the ground engaging face often wears or "washes" unevenly from the lower face of the adaptor, requiring replacement or refurbishment. The life of the adaptors is usually five to ten times the life of the teeth, and, adaptors -2currently in use usually require replacement after about million Bank cubic metres (BCM) of service.

It is an object of the present invention to provide a wear resistant adaptor with improved wear characteristics over adaptors currently in use. Other objects and advantages of the invention may hereinafter become apparent.

With the foregoing in view, this invention in one aspect resides broadly in an adaptor for attaching a ground engaging element to earth moving machinery, said adaptor including: an adaptor blank; a plurality of spaced apart apertures and/or recesses in said blank opening to a lower face of said adaptor blank; a capping of hardfacing on said lower face, said hardfacing comprising a wear resistant material dispersed in a weld matrix.

In another aspect, this invention resides broadly in a method of hardfacing an adaptor for attaching a ground engaging element to earth moving machinery, said method including: providing an adaptor blank; forming a plurality of spaced apart apertures and/or recesses in said blank opening to a lower face of said adaptor blank; substantially filling said apertures with hardfacing comprising a wear resistant material dispersed in a weld matrix, and forming a capping of said hardfacing on said lower face.

Preferably, the apertures are provided by a first set of substantially parallel grooves and a second set of substantially parallel grooves arranged angularly to the first set, said -3grooves being of a depth and a width selected to receive a single bead of hardfacing and being spaced from one another a distance sufficient that substantially no dissolving of the wear resistant material into the weld matrix occurs during the application of the capping. Of course, hardfacing may also be applied to one or more other faces, such as the upper face and/or side faces of the adaptor blank, and the apertures as previously described may be provided in one or more of the other faces or part thereof for better wear resistance.

In such form it is preferred that each set of grooves be arranged substantially at right angles to one another, and substantially at 450 to a line bisecting the lower face of the blank. Accordingly, the first and second sets of grooves will form a cross-hatched pattern across the lower face. It is further preferred that the cross-hatched pattern be formed on a forward part of the lower face of the adaptor blank (that is, the part remote from the connection of the adaptor to the earth moving machinery) and preferably a third set of grooves is provided substantially at right angles to the bisecting line across the remainder of the lower face, the lower face being capped with hardfacing as previously described. In such form, the third set of grooves preferably retains the spacing as previously described which is selected such that the wear resistant material remains undissolved during the application of the hardfacing to the grooves and the capping.

Preferably, the capping is constructed from a plurality of parallel beads of weld laid against one another. The weld matrix for the hardfacing material is preferably formed from ARM-2 weld -4wire as manufactured and supplied by Abrasion Resistant Materials Pty Ltd, and applied in a metal-inert-gas atmosphere to coat the required net area required for the weld. This weld wire conforms to BS2901 Part 1 1970A18 and AWS A5.18 E70S-6. It is also preferred that the wear resistant material be tungsten carbide grit, and that the grit be added into the molten weld pool during the welding process, by any suitable means.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the following drawings which illustrate a preferred embodiment of the invention, and wherein: Fig. 1 is a plan view of the underside of an adaptor according to the invention; Fig. 2 is a plan view of the underside of the adaptor of Fig. 1 with the hardfacing removed; Fig. 3 is a side view of the adaptor of Figs. 1 and 2, and Fig. 4 is a side view of the adaptor of Fig. 4 with the hardfacing removed.

The adaptor 10 shown in Figs. 1 to 4 is of a standard shape which tapers from a large end 20 to a small end 30, the large end being for attachment of the adaptor to a drag-line bucket and the small end being for attachment of a pointed, ground engaging tooth to the adaptor.

The large end is provided with a blind hollow so that the adaptor may be fitted to a standard projection on the drag-line bucket, and includes a convex rear edge 24 which defines one end of a lower face 12. Hardfacing is provided on the lower face generally by a plurality of abutting beads of weld running generally transversely across the lower face of the adaptor. Two side faces 14 and a curved forward edge 34 define the remaining three edges of the lower face. Spaced forward from the convex rear edge and centrally located between the side faces is a Dshaped recess 21 with a flat shoulder face, and the straight side of the towards the rear of the lower face which is adapted to receive therein a fastener (not shown). The recess also has an oval shaped rear aperture 22 extending through the body of the adaptor into the blind hollow of large end.

The small end 30 is provided with a forward projection 31 which projects forward from the curved forward edge of the lower face for attachment of the ground engaging tooth. The forward projection includes a convex forward edge 32 forming the forward edge of a curved lip 33 which is forward of two sloping lands which are arranged astride a parallel faced forward land 36 which in turn surrounds a square forward aperture 37 extending through the forward projection.

Referring in particular to Fig. 2, the lower face is shown before the hardfacing is applied, and is referred to as the lower face profile 18. The lower face profile includes a first set of grooves shown typically at 15 which are set at 450 to a lateral line 17 extending across the adaptor forward from the D-shaped recess. A second set of grooves are set at 450 to the lateral line and at right angles to the first set to provide a crosshatched pattern of parallel spaced apart grooves across a forward portion 18 of the lower profile of the adaptor from the curved forward edge to the lateral line and between the side faces.

-6- A third set of six grooves shown typically at 26 are provided parallel to the lateral line (that is, at right angles to a line bisecting the lower face), and extending partway across a rear portion 28 of the lower profile from each of the side faces. There are two alternative forms of the third set of grooves shown in Fig. 2, those on the left of the Fig. as shown being of substantially the same length, and those on the right decreasing in length from the rear to the front of the lower profile.

The side face 14 (from the right-hand side of Figs. 1 and 2) is shown in Fig. 3, and with the hardfacing removed as a side profile 13 in Fig. 4. The side profile has a fourth set of grooves shown typically at 43 and which are parallel to one another (and at right angles to the plane of symmetry) extending from the lower profile 11 to an alignment line 44 parallel to the lower profile, or slightly tapering towards the lower profile from the rear to the front of the adaptor. It can also be seen that the forward projection 31 has a projection side face 38 which extends rearward into a rebate in the side face between two curved corner portions 39.

In use, six or more adaptors 10 of the present invention may be used on the bucket of a drag-line by inserting a corresponding projection on the bucket into the hollow of the large end of a corresponding adaptor and attaching the adaptor to the bucket in the normal manner by inserting a fastening through the rear aperture 22. A ground engaging tooth is attached to the small end 30 by inserting the forward projection 31 into a corresponding hollow in the ground engaging tooth, and fixing the -7tooth to the forward projection by inserting a corresponding fastening through the forward aperture 37.

In forming the body of the adaptor, including the grooves to be filled with hard-facing, it is believed that the spacing between the grooves should be such at the application of the hard-face capping to the lower face does not result in the dissolving of tungsten carbide grit into the metal matrix of either the weld or the substrate metal of the body of the adaptor.

It is believed that adaptors formed in accordance with the invention will have increased service life due to the increased strength of the hard-face capping applied to the lower face of the adaptor. It will be appreciated that the apertures which are first substantially filled with hardfacing are of a depth, width and spacing selected that the wear resistant material is substantially undissolved in the hardfacing of the capping and in the apertures. It will also be appreciated that there may be some intermingling of the weld matrix into the material from which the adaptor blank is formed.

An experimental example of the adaptor of the invention was made in which the diagonal spacing between the first and section sets of grooves was 40 mm, the spacing between the third set of grooves was 38 numm and the lateral line was forward of the recess mm. The forth set of grooves were 50 mm in length and spaced from one another by 38 mm. These grooves were formed in an adaptor blank having a length of 483 mm, a width at the large end of 406 mm and a width at the small end of the forward projection N'i -8of 356 mm. The height of the blank was 305 mm at the large end at 248 mm at the small end.

It will be realised that the above description is illustrative of one or more examples of the invention and that all modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as defined by the following claims.

Claims (3)

1. An adaptor for attaching a ground engaging element to earth moving machinery, said adaptor including: an adaptor blank; a plurality of spaced apart apertures and/or recesses in said blank opening to a lower face of said adaptor blank; a capping of hardfacing on said lower face, said hardfacing comprising a wear resistant material dispersed in a weld matrix.

2. An adaptor according to Claim 1, wherein said apertures are provided by a first set of spaced substantially parallel grooves and a second set of spaced substantially parallel grooves arranged angularly to the first set, said grooves being of a depth and a width selected to receive a single bead of hardfacing and being spaced from one another a distance sufficient that the wear resistant material is substantially undissolved in the weld matrix.

3. An adaptor according to Claim 2, wherein each set of grooves is arranged substantially at right angles to one another, and substantially at 450 to a line bisecting the lower face of said blank, the first and second sets of grooves being formed in a forward part of the lower face of the adaptor blank remote from the connection of the adaptor to the earth moving machinery and including a third set of grooves substantially at right angles to the bisecting line across the remainder of the lower face, the lower face being capped with said hardfacing. Dated this 2 0 th day of November, 2000 THE TRACK SHOP PTY LTD By Their Patent Attorneys AHEARN FOX I