AU596351B2 - Tillage points - Google Patents

Description

AUSTRALIA

Patents Act 59-6351 COMWPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: 5L 1 to~4 '+A Lodged: Complete Specification Lodged: Accepted: Published: Tis document contains the tflndments made under Section 49 and is correct for P rinting.

Priority

A.

Related Art: *0 4 o 4# 4 #4 4444 4 n. #4 4444 4 4 #4 44 4444 #44* 4 #4 44 4 444 4 4 #4 44 4 #4*4 4 #4 44 4 It Name(s) of Applicant(s): APPLICANT'SREF.: C.A.P. of PG 9459/85 A~WOO&CLG..~1-~- Address(es) of Applicant(s): t nunOrA.t -Per Western Australia, Austr, lia 0 Actual Inventor(s); Address for Service is: PHILLIPS, ORMONDE AND FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne, Australia, 3000 Complete Specification for the invention entitled: TILLAGE POINTS Tile following statement is a full description of this invenGz. 'ncluding the best method of performing it known to applicant(s): PlIW3184 ill This application is for a Patent of Addition to Australian Patent 570643, the disclosure of which is incorporated herein by reference.

The invention of this application relates to an improvement or modification in agricultural shares, and in particular to such shares known as scarifier, cultivator, combine or tillage points.

Agricultural shares used for scarifying and tilling conventionally are pressed from steel. However, while tough and having good resistance to impact with roots and rocks, they are prone to rapid wear. Indeed, the limited wear resistance of pressed steel agricultural shares is such that they can reqvire replacement every 24 hours, or less. Not only is the replacement cost high, but considerable time can be lost during changeover of the shares of an agricultural machine.

The present invention is directed to providing such agricultural shares having improved wear resistance, but which still retain sufficient resistance to impact.

According to the present invention there is provided an agricultural share formed by casting a ferrous alloy having from 1 to 5 wt.% carbon; the alloy having a sufficient quantity of chromium, and being cast, to provide a microstructure of eutectic iron-chromium carbides in a matrix of austenite in the as cast condition or martensite and/or retained austenite and precipitated secondary carbides in a heat treated condition, said agricultural share having a forward working end in the I form of a flattened, protruding arrow-head and a rearward /i mounting end; the forward end defining a protruding nose and, on each side of the nose, a respective forwardly facing work S 30 edge which extends rearwardly and laterally from the nose to a Srespective one of two laterally opposed heels; the rearward end defining mounting means intermediate and rearwardly of the 4 heels and providing respective rearwardly facing trailing edges extending 0

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from each heel toward the mounting means; the share having upper and lower major surfaces each bounded by the work edges and the trailing edges and a thickness between those surfaces which decreases rearwardly of a line extending between the heels. The alloy preferably has at least 10% chromium.

The alloy may contain one or more of the alloying elements nickel, copper, silicon, magnanese, vanadium, molybdenum and titanium. It also may have incidental S impurities normal in ferrous alloy production. Most conveniently, silicon and copper contents do not exceed each; manganese, vanadium, nickel, molybdenum and titanium do not exceed 10% each; and chromium does not Sexceed 35%. One particularly suitable alloy has the following composition: carbon 2.4 to 3.6% nickel 0.1 to copper 0.1 to molybdenum 0.1 to i 20 silicon 0.1 to manganese 0.2 to chromium 10.0 to 30.0% balance iron, apart from incidental impurities.

All percentages in the foregoing are on a weight-weight basis.

Agricultural shares such as scarifier or tillage points produced in accordance with this invention have superior wearing properties compared to pressed tillage '1 points. The degree of hardness dictating wearing properties and the degree of toughness may be varied by various methods of composition or controlled heat Streatment. These heat treatments may cover the normal processes of annealing, and hardening of selective areas attained by flame, induction or immersion heating followed by controlled quenching with a liquid. The liquid may be oil, water, brine or other suitable quenchants.

ALi The shares of the present invention may retain less zS39 hickness in ihe mounting area where they are attached to

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agricultural implements and the thickness in other areas can vary according to the wear pattern encountered in the work area. The shares of the present invention may be cast with an elongated raised section which forms an integral part strengthening the point and enables the alternative of a bolt head retention device to be incorporated in the casting, thus avoiding the need for the supply of any specially shaped bolts which are frequently required to mount pressed points.

The line extending between the heels may curve forwardly from each heel. Also, a ridge extending between the

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t ,siJ1T o~-3anose and mounting means may be defined in said upper surface due to respective lateral portions of each of the upper and lower surface being mutually inclined. The lower surface may have locally raised sections for location purposes extending beyond the bolt hole.

Reference now is made to the accompanying drawings, in which: Figure 1 shows a perspective view of a first scarifier or tillage point according to the invention; Figure 2 shows the point of Figure 1 in a rear elevation; and Figures 3 and 4 show in a view similar to Figure 1, two further points according to the invention.

In each of the figures, 12 designates the mounting area of the share; while 14 designates an aperture by which the share can be releasably secured to a suitable agricultural Smachine. Reference 16 designates a transverse sweep, depicted by the broken line, comprising a wear area; that area extending intermediate mounting area 12 and nose 18 from one heel 24 to the other heel.

Each of the three forms of share illustrated is cast From an alloy according to the invention. The share is formed w th a central ridge on its upper surface which extends from below aperture 14 to nose 18. Between the upper and lower 4surfaces, the shares most conveniently are of increased thickness 4 along line 16 relative to the thickness at mounting area 12.

That transverse extent of increased thickness may decrease in S the direction of the ridge toward area 12, as shown by the tapered edge extending from heels 24 and 9een in Figure 2.

Aperture 14 is for receiving a bolt by which the a share can be secured in an agricultural machine; aperture 14 having an enlarged bolt head receiving recess. Alternatively, above and below aperture 14, in the direction of the ridge, bolt head retaining shoulders can be provided, or a bolt can be cast into area 12 at the time of forming the share.

The shares may be cast in any convenient manner.

However, alloy additions and/or cooling conditions are controlled so as to achieve a microstructure as detailed above. The shares 39 so formed are found to have improved wear resistance compared FY -4with pressed steel shares. The reduced thickness at mounting area 12 compared with the thic.kness along line 16 results in no reduction in strength in area 12 and, hence, maintains resistance to breakage.

The unique variation in section between the wearing areas and the mounting area not attainable with pressed steel points gives the cast alloy point the ability to retain configuration throughout its working life.

As detailed above, the share may be heat treated to vary the balance between wear resistance and toughness so as to enable optimum wear resistance for the wear area and optimum toughness in mounting area 12.

The heat treatment may be effective throughout the share or, if required, it may be substantially restricted to the thickness of the wear area.

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Claims (8)

1. An agricultural share, .h 4i 1 1 4- n formed by casting a ferrous alloy having from 1 to 5 wt.% carbon; the alloy having a sufficient quantity of chromium, and being cast, to provide a microstructure of eutectic iron-chromium carbides in a matrix of austenite in the as cast condition or martensite and/or retained austenite and precipitated secondary carbides in a heat treated condition, said agricultural share having a forward working end in the form of a flattened, protruding arrow-head and a rearward mounting end; the forward end defining a protruding nose and, on each side of the nose, a respective forwardly facing work edge which extends rearwardly and laterally from the nose to a respective one of two laterally opposed heels; the rearward end defining mounting means intermediate and rearwardly of the heels and providing respective rearwardly facing trailing edges extending 2 from each heel toward the mounting means; the share 20 having upper and lower major surfaces each bounded by the work edges and the trailing edges and a thickness between those surfaces which decreases rearwardly of a line extending between the heels.

2. An agricultural share according to claim 1, wherein said alloy has at least 10 wt.% chromium.

3. An agricultural share according to claim 1 or claim 2, wherein said alloy contains at least one of the alloying elements nickel, copper, silicon, manganese, vanadium, molybdenum and titanium.

4. An agricultural share according to claim 3, wherein dthe content of silicon and copper does not exceed wt.% each; manganese, vanadium, nickel, molybdenum and titanium does not exceed 10 wt.% each and chromium does not exceed 35 wt.%. An agricultural share according to claim 3 or claim 4, wherein said alloy has a composition comprising: carbon 2.4 to 3.6 wt.% ALIt nickel 0.1 to 7.5 wt.% J3 copper 0.1 to 1.0 wt.% -6- c- :-rI vnr r- molybdenum 0.1 to 3.5 wt.% silicon 0.1 to 1.0 wt.% manganese 0.2 to 1.5 wt.% chromium 10.0 to 30.0 wt.% the balance, apart from incidental impurities, being iron.

6. An agricultural share according to any one of claims 1 to 5, wherein said line curves forwardly from said heel.

7. An agricultural share according to any one of claims 1 to 6, wherein a ridge extending between the nose and mounting means is defined in said upper surface by respective lateral portions of each of said surfaces being mutually inclined.

8. An agricultural share according to any one of claims 1 to 7, wherein the lower surface has locally raised sections for location purposes in mounting the share, said raised sections extending beyond a bolt hole.

9. An agricultural share according to claim 1, substantially as herein described with reference to Figures 1 and 2, or to Figures 3 or 4, of the accompanying drawings. DATED: 14 July 1989 PHILLIPS ORMONDE FITZPATRICK Attorneys for: AGNEW GLOUGH LIMITED V4 -7-