AU669497B2 - Improvements to grader blade assemblies - Google Patents

Description

AUSTRALIA

P/00/011 Regulation 3.2 Patents Act 1990 44 00i~ 1 0 4 40 01 .00 4

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: IMPROVEMENTS TO GRADER BLADE ASSEMBLIES The following statement is a full description of this invention, including the best method of performing it known to me: j- 4

B

E

i- 3-- 1-1- 00 00 00 0 0 o to Oe 00 0 qoy 2 This invention relates to improvements in cutting blade assemblies of road graders of the type having a transversely disposed mouldboard with a detachable ground engaging blade.

Commonly, motor graders are provided with a mouldboard having affixed thereto, say by bolting, a straight edged or serrated cutting blade, the latter being provided with a plurality of integrally formed cutting edges. Hard road surfaces such as clay and gravel roads often found in country areas and mining haulways develop, after protracted use an extreme degree of compaction with corrugations and irregularities in the roadway surface. It has been found that motor graders with conventional straight edges cutting blades tend to skid uneffectively over the compacted road surface.

On the other hand, serrated cutting edges are subject to breakage and this causes the motor grader to be stopped whilst the cutting blade is unbolted and a replacement blade bolted on the mouldboard.

This arrangement is obviously time-consuming and relatively expensive as damage say to only one or two individual cutting edges may require the entire serrated cutting blade to be replaced.

The present invention is concerned particularly with the grading of unsealed earthen road surfaces which may become highly compacted after prolonged periods of use. Typical of such hardened earthen road surfaces are mining haulways which are subjected to high levels of traffic with heavily laden vehicles.

I

t ar^-rx- 3 It has been found that the lise of pointed cutting edges of a grader blade causes the brittle compacted earth to fracture enabling the pointed cutting edges to deeply penetrate the earth surface causing the motor grader to stall. Even if the motor grader had sufficient power to overcome stalling the grading action would result in a loose uncompacted road surface which would quickly develop surface irregularities such as pot holes, corrugations, ruts and the like oo due to the heavy traffic. It is important therefore in maintenance of o oo~oo such earthen roadways to be able to smooth out surface irregularities 10 and at the same time maintain a highly compacted road surface.

00 04 With conventional grader blades, the continuous cutting edge o: prevents the blade from penetrating the upper compacted layer and the blade tends to simply skid along the road surface. There is a need therefore for a cutting pick for a grader blade assembly which in use is effective to shave the compacted road surface to remove ;irregularities therefrom without causing the compacted road surface to become fractured and lose its structural integrity.

The present invention aims to overcome or at least alleviate some of the above disadvantages by providing a replaceable cutting pick assembly for motor graders. The replaceable pick to the present invention is provided with a hardened tip to provide an efficient cutting action and in use may be easily replaced by a further pick in the event of damage or wear so that operational downtime is 4 reduced. Furthermore the need to replace the entire cutting blade assembly is eliminated in the event of damage to only some of the cutting picks. Other objects and advantages of the invention will become apparent from the following description.

According to the invention there is provided a cutting blade assembly for attachment to the mouldboard of an earth grader, said blade assembly comprising:an elongate mounting member adapted for attachmen along a o 0 lower edge of a grader mouldboard, said mounting members including oo 10 along its lower edge a plurality of spaced sockets for releasably oooo S0 locating cutting picks in spaced relationship; and 0 a plurality of removable cutting picks each locatable in a respective socket to form a discontinuous cutting edge along a lower 4 00 edge of said blade assembly, each said cutting pick having: a supporting shank includiny retention means for releasably retaining said supporting shank in a respective one of said sockets; and a body portion having a substantially planar leading surface, said leading surface including a hardened metal alloy working face having a transverse straight cutting edge adjacent a free end of said body portion remote from said supporting shank, said free end of said body portion extending rearwardly away from said cutting edge to form a substantially planar ground engaging surface.

i~ In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:- FIG 1 is an elevation view illustrating portion of a cutting blade assembly incorporating replaceable cutting picks; FIG 2 is a cut away sectional view illustrating the cutting blade o assembly of FIG 1 secured to a grader mouldboard; °°FIG 3 is an isometric view of a typical replaceable pick forming o 10 part of the present invention; and S0 FIG 4 is a view in the direction A-A of FIG 2.

Referring to the drawings there is illustrated a cutting blade assembly 10 including a mounting member 11 which is preferably *0,icast and which is provided with a first arcuate portion 12 for attachment to a mouldboard 13 of conventional form and second mounting portion 14 having a plurality of spaced parallel bores or sockets 15 of circular cross section formed there which are adapted to mount respective replaceable cutting picks 16.

As shown, the arcuate portion 12 on the mounting member 11 is apertured at spaced positions 17 which align with corresponding apertures 18 in the mouldboard 13 so that respective bolts may be passed therethrough to mount the member 11 to the mouldboard 13 as shown. The respective bores 15 in the mounting portion 14 are ucl 6 stepped outwardly at 19 adjacent their upper ends to define a shoulder and the mounting portion 14 includes a downwardly dire"i~ed flange the purpose of which will hereinafter become apparent.

As shown in FIGS 2 and 3 each replaceable cutting pick 16 includes a main body portion 21 and a solid cylindrical mounting shank portion 22 of such diameter as to be closely received with a bore or socket 15 in the mounting portion 14 of member 11. The main body portion 21 of the pick 16 includes a substantially planar leading surface 0 o o 00 21' which has supported at its operative lower end 21" a working face 10 in the form of a generally rectangular hardened tip 23' preferably formed of a tungsten alloy which extends the full width of surface 21'. The 0 rectangular configuration of tip 23 defines a generally linear lower o00:°0 cutting edge 23' so that maximum operative cutting area is achieved o o o .:00 and so that in use a proper finish ground surface will be formed.

The operative lower end of body 21 extends rearwardly of °lower cutting edge 23' to form a planar ground engaging surface which resists penetration by pick 16 of compacted earth surfaces. It will be clear to a skilled addressee that with the rearwardly inclined face of body portion 21, the area of the ground engaging face 21" increases as the pick wears through use.

The shank portion 22 is preferably provided with a broad 7 groove 24 adjacent its upper end to receive a split connecting clip The clip 25 is of generally annular form and preferably formed of resilient materials such as spring steel strip. Furthermore the clip is provided with a number of outwardly directed projections or dimples 26.

As shown in FIG 2, each pick 16 is adapted to be engaged with the mounting portion 14 of the member 11 so that the shank portion 22 is closely accommodated within a bore 15 and the groove 24 of the shank portion 22 located adjacent the stepped portion 19 of the bore 15. n this position the clip 25 may spring resiliently outwardly so that Qooo o a 00 :ooo 10 the dimples or projections 26 are disposed within the stepped portion 19 00o00of the bore for location behind the shoulder 20 to maintain the pick in an operative engaged attitude. Furthermore a rear face 27 of the body ::0000 portion 21 of the pick 16 is located adjacent or in abutment with the 0000°° flange 20' so that rotation of the point 16 relative to the member 11 is 15 eliminated or substantially reduced.

0:0 When it is desired to remove the pick 16, the clip 25 must be radially compressed so that the dimples do not project radially outwardly beyond the diameter of the bore 15. Of course, this may be achieved by a sharp tap of a hammer on the top end of the shank portion 22 which will cause the dimples 26 to ride up along the shoulder 20 so as to effectively radially compress the clip It will thus be seen that when it is necessary to change one or 8 more picks, it is a simple procedure to remove the worn pick and replace it with a new pick which may again be simply tapped into position with the clip 25 beinj radially compressed by virtue of engagement of the dimples 26 with the leading ends of the bore until the enlarged diameter portion 19 of the bore 15 is reached whereupon it will spring outwardly to positively locate the pic. in position. Of course it will be realised that the clip 25 may be in many 0different forms; for example, the clip may simply comprise a rubber oaoo 0000 ring which resiliently expands outwardly when the point 16 is located 0 10 in its operative position to be partially located in the groove 19. In an alternative arrangement, the mounting portion 14 of the holder may 0 be provided with a plurality of apertures adapted to be aligned with corresponding apertures in the shank portion of the pick so that a pin 0 0 may be inserted through aligned apertures to maintain the pick in its operative attitude.

0. Whilst the above has been given by way of illustrative example of the invention, it will of course be realised that many modifications and variations may be made to the above described embodiment by persons skilled in the art without departing from the broad scope and ambit of the invention as defined by the appended claims. For example, in some instances the clip 25 may be totally eliminated and the shank 22 tapered to mate with a tapered portion of the bore to frictionally hold the pick in position.

ato 1 m I I d" I

Claims (8)

1. A cutting blade assembly for attachment to the mouldboard of an earth grader, said blade assembly comprising:- an elongate mounting member adapted for attachment along a lower edge of a grader mouldboard, said mounting member including along its lower edge a plurality of spaced sockets for releasably locating cutting picks in spaced relationship; and a plurality of removable cutting picks each locatable in a o respective socket to form a discontinuous cutting edge along a lower o 10 edge of said blade assembly, each said cutting pick having: o a supporting shank including retention means for releasably 0. retaining said supporting shank in a respective one of said sockets; and S:0 a body portion having a substantially planar leading surface, said leading surface including a hardened metal alloy working face having a transverse straight cutting edge adjacent a free end of said body portion remote from said supporting shank, said free end of said body portion extending rearwardly away from said cutting edge to form a substantially planar ground engaging surface.

2. A cutting blade assembly as claimed in claim 1 wherein restraint means are provided to prevent relative rotation between each said cutting pick and respective socket in said mounting member. L

3. A cutting blade assembly as claimed in claim 2 wherein said restraint means comprises a shouldered abutment on said mounting member which shouldered abutment is adapted to engage with a corresponding abutment on the body portion of each said cutting pick.

4. A cutting blade assembly as claimed in any preceding claim wherein adjE,.ront cutting picks are spaced by a distance substantially oo equal to the transverse width of a cutting pick working face. 0°05. A cutting blade assembly as claimed in any preceding claim 10 wherein said retention means comprises a resilient clip member.

6. A cutting blade assembly as claimed in any preceding claim wherein said mounting member includes apertures alignable with blade mounting apertures in said mouldboard whereby said mounting 2, member is attachable to said mouldboard by securing means passing through aligned apertures in said mounting member and said mouldboard.

7. A cutting blade assembly substantially as hereinbefore described with reference to the accompanying drawings.

8. In combination, an earth grader mouldboard and a cutting blade assembly as claimed in any preceding claim. i i tl I I 11

9. An earth grader comprising a cutting blade assembly as claimed in any preceding claim. DATED this Twenty-second day of August 1995 THOMAS ANTHONY MEYERS By his Patent Attorney FISHER KELLY 00 00 oo 0 0 0 0 000 a 0000 ea 00 00 00 0 0 0 0 00 o ioo 0 ooo i o o 0 o0 ooooo 0 0 o o 00 0 _r i- I I 12 ABSTRACT A cutting blade assembly attachable to the mouldboard of an earth grader comprises an elongate member with a plurality of sockets to releasably locate a plurality of spaced cutting picks. Each pick has a shank releasably locatable in a respective socket and a body portion having a planar leading surface with a hardened metal alloy working face and a transverse straight cutting edge. A free end of the body 0o 1, portion adjacent the cutting edge has a substantially planar ground C o engaging surface extending rearwardly away from said cutting edge. 0 oe o o0 0 0 o o «ld J .i t