AU779800B2

AU779800B2 - Improvements in ground engaging blades for grader moldboards

Info

Publication number: AU779800B2
Application number: AU76121/01A
Authority: AU
Inventors: Timothy Stuart Falkenhagen
Original assignee: Track Shop Pty Ltd
Current assignee: Track Shop Pty Ltd
Priority date: 2000-09-29
Filing date: 2001-09-28
Publication date: 2005-02-10
Anticipated expiration: 2021-09-28
Also published as: AU7612101A

Description

P/00/011 Regulation 3.2 *0 0 00 0 0 0 0 000000 0 0000 0 0 0000 COMMONWEALTH OF AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventor(s): Address for Service: **Title: Invention Title: THE TRACK SHOP PTY LTD Timothy Stuart Falkenhagen AHEARN FOX Patent Trade Mark Attorneys GPO Box 1149 Brisbane Queensland 4001 "IMPROVEMENTS IN GROUND ENGAGING BLADES FOR GRADER MOLDBOARDS" The following statement is a full description of this invention, including the best method of performing it known to us: -1- IMPROVEMENTS IN GROUND ENGAGING BLADES FOR GRADER MOLDBOARDS THIS INVENTION relates to improvements in ground engaging blades for grader moldboards.

Although the invention has been developed primarily for use with grader moldboards it will be appreciated that the invention is not limited to this particular field of use.

Grader moldboards frequently have one or more replaceable ground engaging blades attached so that the part of the @00@@0 moldboard which engages the ground and wears away may be readily replaced. Hereinafter, that part of the moldboard to which the ground engaging blades are attached will be referred 'to as a moldboard stub. Hardfacing has sometimes been applied to the heel portion of the blades in an effort to increase service life since it is from the heel that the blades commence 15 and continue to wear.

Sometimes, the ground engaging blade may be referred to as a "grader blade" or a "blade insert", and sometimes the assembly of the grader blade to the moldboard stub may be referred to as a "grader blade". In this specification, the 20 term "blade" is used to refer to the removable and replaceable element attachable to a moldboard stub to form a grader moldboard when so attached.

The present invention aims to provide an improved ground engaging blade for a grader moldboard having a longer service life than ground engaging blades of the prior art.

With the foregoing in view, the present invention resides broadly in a ground engaging blade for releasable attachment to a moldboard stub, the blade including: a front face; a rear face spaced from said front face and arranged such that at least part of said front and rear faces taper to meet along a lower edge; two spaced ends; one or more recesses (referred to as "lower edge recesses") in and extending along said lower edge and opening generally downward; S: one or more recesses (referred to as "rear face recesses")

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:i0 in and extending along and opening to the rear face and spaced from said lower edge; and hardfacing in said recesses, and, in the form of a hardfacing layer, on at least some of the rear face, said hardfacing layer substantially covering the hardfacing in said i15 rear face recess or recesses and said hardfacing layer covering 0*OS at least some of said lower face recess or recesses.

The lower edge may be provided as a discontinuous lower edge comprising a plurality of lower edge portions separated by a corresponding plurality of notches, each notch being S. 20 provided between adjacent lower edge portions. In such an arrangement, the lower edge recess is preferably provided as a set of lower face recesses, each of recess extending along the lower edge of each lower edge portion in regular spaced relationship. The rear face recess or recesses may be provided either as a continuous recess from one end of the blade to the other if provided above the notches, or if not provided above the notches, as a set of rear face recesses, each member of -3which extends fully along the rear face of each respective lower edge portion.

Preferably, the front and rear faces are curved about a horizontal axis or focal line forward of the front face.

It will be appreciated that terms such as "upper", "lower", "downward", "horizontal" and the like refer to the blade in its normal orientation, and do not limit the invention to any *fw: particular orientation.

000000 0 Preferably, the recesses are in the form of a groove 00 :10 running along at least some of the lower edge or edge portions S. and/or the rear face. It is also preferred that each groove 0000 or recess be of a width and depth sufficient that it be filled by from one to three beads of hardfacing weld and such that the hardfacing layer covers the or each groove or recess. In a preferred form, the rear face recesses and the lower edge

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00. recesses are all in the form of a groove having a semicircular 06:0 or part circular cross section, each lower edge groove being provided along the entire length of the lower edge or each lower edge portion (as the case may be) and the rear face groove being provided along the entire length of the rear face.

*0 00 Preferably, the layer of hardfacing is formed from a plurality of weld beads laid up beside one another in edge-toedge abutting relationship, each bead of weld being applied in a longitudinal direction from one end of the blade to the other. It is also preferred that the hardfacing be formed by electric arc welding, from ARM-2 weld wire as manufactured by Abrasion Resistant Materials Pty Ltd, at a suitable current, typically 200 to 260 amps, and a suitable electrical potential, -4typically 22 to 26 volts in a metal-inert-gas atmosphere at a linear rate sufficient to coat the net area required for the bead of weld. The preferred wire conforms to BS2901 Part 1 1970A18 and AWS 5.18 E70S-6. The hardfacing includes tungsten carbide grit added to the molten weld pool during the welding process, by any suitable means, and is preferably mesh size 12/35.

In another aspect, the present invention resides broadly S in a grader moldboard including a ground engaging blade as :10 hereinbefore described operatively attachable to a moldboard stub.

In order that the invention may be more readily understood 0*o and put into practical effect, reference will now be made to the accompanying drawings which illustrate two preferred 15 embodiments of the invention, and wherein: Fig. 1 is diagrammatic sectional view along lines 1-1 of Figs. 2 and 3 of a ground engaging blade according to the *0 invention; Fig. 2 is a diagrammatic front elevation of the ground 20 engaging blade of Fig. 1; and Fig. 3 is a diagrammatic front elevation of an alternative form of ground engaging blade in according to the invention and having notches along the lower edge, but having substantially the same cross-section between the notches as the ground engaging blade of Figs. 1 and 2.

Referring to the Figs. 1 and 2, the ground engaging blade has a front face 11 curved about a horizontal axis or focal line and a rear face 12 spaced from the front face and curved such that at least some of the front and rear faces taper to meet along a lower edge 15. The front and rear faces diverge from one another upwardly and meet with an upper edge face 14 parallel to and spaced from the lower edge. The upper edge face is substantially planar. The blade extends between two spaced ends 18 (one of which is shown in Figs. 2 A lower S edge recess 21 is provided in and extending along the lower edge and a rear face recesses 22 is provided along, and opening :10 to, the rear face and extending from one end of the blade to the other. Hardfacing is provided in each of the recesses as shown at 25, and, in the form of a hardfacing layer 26, is provided on a lower portion of the rear face, the hardfacing layer substantially covering the hardfacing in or on the recesses.

e g..In the ground engaging blade 20 shown in Fig. 3, the same reference numerals are used for the features which do not differ from those of the ground engaging blade 10 of Figs. 1 and 2. However, the lower edge is notched to provide a plurality lower edge portions 28, each lower edge portion being spaced apart by a respective notch portion 29 intermediate adjacent lower edge portions.

The rear face recesses and the lower edge recesses are in the form of a groove having a semicircular cross section, each lower edge groove being provided along the entire length of the lower edge or each lower edge portion (as the case may be) and the rear face groove being provided along the entire length of the rear face for each embodiment of blade (just above the -6notches, of the alternative blade 20). Alternatively, the rear face groove in the alternative blade is provided just below the inner end of the notches and along the entire length of each lower edge portion.

In use, one or more ground engaging blades are attached to a lower and forward facing rebate along a moldboard stub to form a grader moldboard. Generally, either notched or nonnotched blades are selected for a particular grader moldboard and/or application.

The blades are formed in accordance with the invention by machining the grooves in a blank blade (that is, a blade prior to the application of hardfacing), and then hardfacing is added into the grooves by welding one or more beads of hardfacing along and in each groove. The layer of hardfacing is then :15 added to the lower edge of the blade and a lower portion of the o' rear face to form the ground engaging blade in accordance with the invention.

It is believed that the present invention, where the hardfacing is in the form of a composite hardfacing where particulate wear resistant material is added to a molten weld pool, permits extra hardfacing material to be added to the blade without causing excessive dissolution of the wear resistant material as often occurs if multiple layers of composite hardfacing are welded onto a substrate.

-7- Although the invention has been described with reference to one or more specific examples, it will be appreciated by persons skilled in the art that the invention may be embodied in many other forms within the broad scope and ambit of the following claims.

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Claims

1. A ground engaging blade for releasable attachment to a moldboard stub, the blade including: a front face; a rear face spaced from said front face and arranged such that at least part of said front and rear faces taper to meet along a lower edge; S two spaced ends; :0 one or more lower edge recesses in and extending along said lower edge and opening generally downward; 6@@O one or more rear face recesses in and extending along and opening to the rear face and spaced from said lower edge; and hardfacing in said recesses, and, in the form of a hardfacing layer, on at least some of the rear face, said hardfacing layer substantially covering the hardfacing in said .or. rear face recess or recesses and said hardfacing layer covering 0* at least some of said lower face recess or recesses.

2. A ground engaging blade according to Claim i, wherein the lower edge is provided as a discontinuous lower edge comprising a plurality of lower edge portions separated by a corresponding plurality of notches, each notch being provided between adjacent lower edge portions.

3. A ground engaging blade according to Claim 2, wherein said lower edge recess is provided as a set of regularly spaced -9- lower face recesses, each of said lower face recesses extending along the lower edge of each lower edge portion.

4. A ground engaging blade according to Claim 3, wherein the rear face recess or recesses are provided as a continuous recess or recesses from one end of the blade to the other above the notches. .oe

5. A ground engaging blade according to Claim 3, wherein the :i0 rear face recess or recesses are provided as a set of rear face recesses below the notches, each member of said set extending substantially fully along the rear face of each respective lower edge portion. :15

6. A ground engaging blade according to Claim i, wherein the o recesses are in the form of a groove running along at least some of the lower edge or edge portions and/or the rear face.

7. A ground engaging blade according to Claim i, wherein the 20 layer of hardfacing is formed from a plurality of weld beads .00 o laid up beside one another in edge-to-edge abutting relationship, each bead of weld being applied in a longitudinal direction from one end of the blade to the other.

8. A grader moldboard including a ground engaging blade according to Claim 1 operatively attachable to a moldboard stub.

9. A ground engaging blade substantially as hereinbefore described with reference to Fig. 1 and Fig. 2. A ground engaging blade substantially as hereinbefore described with reference to Fig. 1 and Fig. 3. Dated this 2 8 th day of September, 2001. THE TRACK SHOP PTY LTD S by their Attorneys *O

:10 AHEARN FOX a 000* e* o ft