AU652524B1

AU652524B1 - A self-sharpening ripper point

Info

Publication number: AU652524B1
Application number: AU59344/94A
Authority: AU
Inventors: Eugene Tsykin
Original assignee: NATURAL RESOURCES ENGINEERING
Current assignee: NATURAL RESOURCES ENGINEERING Pty Ltd
Priority date: 1994-04-08
Filing date: 1994-04-08
Publication date: 1994-08-25
Anticipated expiration: 2014-04-08

Description

25 24

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Address of Applicant: Actual Inventor: Address of Service: Natural Resources Engineering Pty Ltd 3/2 Malsbury Street Bicton W.A. 6157 EUGENE TSYKIN Natural Resources Engineering Pty Ltd 3/2 Malsbury Street Bicton W.A. 6157 Standard Complete Specification for the invention entitled: A SELF-SHARPENING RIPPER POINT The following is a full description of this invention, including the best method of performing it known to me:

TITLE

A SELF-SHARPENING RIPPER POINT BACKGROUND OF THE INVENTION This invention relates to a ripper point for ripping the ground, and in particular, but not exclusively, to a ripper point for ripping brittle and hard ground. In many environmental, mining and civil engineering projects, fragmentation of brittle and/or hard layers of ground is an important step. For example, as an initial step of mining, it is often necessary to fragment hard deposits or layers S. overlying a mineral deposit. In a further example, in some areas where reafforestation is to be undertaken, cemented layers of soil have been detected close to the surface.

The breaking up of this cemented layer is considered very important for tree establishment as it allows much better root penetration through the soil.

PRIOR ART One means of ripping and fragmentation of the ground is to use a tractor pulled ripper to which a ripper point is attached. Until recently, the design of ripper points for fragmentation and ripping of the ground have remained substantially the same over the years, while tractor design has rapidly advanced providing greater horsepower.

Hitherto, in order to increase ripping efficiency, larger tractors and ripping points have been used. Very little research has been conducted on ripper points per so as a means to increase ripping efficiency of hard ground.

The present applicant has found that in practice there is a common problem when hard and brittle ground is being fragmented or ripped with conventional ripper points: the energy required for downward penetration and wear of lower surfaces of ripper point's body are excessive. Commonly, the tip of ripper point is chisel shaped. A narrow tip would have better penetration. However, a narrow tip would o. not be durable because of fast blunting of leading parts of .fle the point.

One of several possible ways to reduce wear of ripper points is utilization of hard inserts with a significantly smaller cross-section than the cross-section of a ripper point. The use of these hard inserts, produced say of tungsten carbide, is common in 'design of smaller tools for fragmentation of hard ground. However, repeated attempts 20 to use such inserts with ripper points for large tractors have been unsuccessful. Hard inserts traditionally installed along the line of symmetry between the upper leading and lower leading surfaces of the point are undermined by wear of lower surfaces and lose their support from underneath. As a result, short inserts fall out and the long ones are broken. This is the main reason why hard inserts of this kind are not used with large machinery for fragmentation of hard and abrasive ground.

4 In this regard, the applicant has discovered that, an untraditional positioning of a hard insert can solve the problem. To eliminate undermining of hard inserts from underneath, the hard insert positioned within the body of a ripper point should be oriented steeper than the line of symmetry between the upper leading and lower leading surfaces of the body.

0* e *2 0020 oe *eo SUMMARY OF THE INVENTION According to one aspect of the present invention for ripping the ground is provided a ripper point comprising: a body with a leading edge positioned substantially below the centre line, a hard insert of cylindrical, conical, prismatic or pyramidal shape, fixed inside the body, close to the leading edge, perpendicular to it wherein the angle between the axis of the insert and the upper leading surface should be smaller than the angle between the said axis and the lower leading surface.

Vertical penetration of a ripper point into hard ground is critical for ripping productivity. Said vertical ::'penetration depends on downward specific pressure of the point onto the ground. The lower area of contact between 20 the ripper point and the ground should be as small as possible to increase pressure and improve penetration.

However, high specific pressure causes fast wear of the ripper point from underneath. This wear tends to enlarge the contact area and make the penetration worse. In this way, wear of ripper points from underneath determines both productivity of ripping and durability of ripper points.

A hard insert installed within the ripper point's body can solve the problem. Wear of such hard insert is slower than wear of the material of the frontal parts of body 1 surrounding the insert and causes the insert to protrude when the point is in use. The protruding insert accounts for most of the contact area between the ripper point and the ground. This area is relatively small. Also, the protruding insert protects the lower surface of the ripper point's body located behind it from excessive wear. The greater the insert is protruding, the better the lower surface of the body is protected. However, an insert 10 which is protruding excessively has inadequate support from underneath and may be broken.

oooe Ideally, the insert should protrude from the body only marginally and the ripper point remains sharp even after a prolonged ripping. Such self-sharpening can be achieved by o:oe equalising of wear of the frontal parts of insert and of frontal parts surrounding body. Such equilibrium can be achieved by changing the angle between the axis of the *o eo insert and the lower surface of the body and by changing the dimensions and mechanical properties of the insert.

The harder is the ground, the greater should be said angle and the thicker the insert.

Field tests showed that productivity of sel fsharpening ripper points with hard inserts is 11-20% higher and wear is 3.5-4.0 times slower than the corresponding results for prior art ripper points.

DESCRIPTION OF THE DRAWINGS Embodi:x.-nts of the present invention will now be described by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a perspective view of the embodiment of a self-sharpening ripper point.

Figure 2 shows a top view of the embodiment of a self-sharpening ripper point.

Figure 3 shows a bottom view of the embodiment of a self-sharpening ripper point.

Figure 4 shows a side view of the embodiment of a self-sharpening ripper point.

represented represented represented represented e eeeQ Figure 5 shows a longitudinal section of the represented embodiment of a self-sharpening ripper point.

Figure 6 shows a cross-section A-A of the represented embodiment of a self-sharpening ripper point as indicated in Figure DESCRIPTION OF THE PREFERRED EMBODIMENT The represented embodiment of the self-sharpening ripper point is illustrated in Figures 1 to 6. The point comprises a body 1 having an upper leading surface 2 and a lower leading surface 3. Both these surfaces converge forward. The leading edge 7 is located well below the centre line 8 of the body 1 to provide an angle between the upper leading surface 2 and the centre line 8 sufficient to accommodate a steeply positioned hard insert 6. A 10 cylindrical hard insert 6 is fixed inside the body 1 close .:ee to the leading edge 7 and perpendicular to it. The axis of ooo the hard insert 6 is parallel to the upper leading surface 2. A distance from the upper leading surface 2 to the hard insert 6 is small, in order to decrease frontal contact area between the ripper point and the ground. The length of the leading edge 7 is several times smaller than the greatest width of the body. Such pointed shape provides a relatively small contact area between the ripper point and the ground. This reduces the forces require' for 20 penetration and increases ripping productivity. Side lower egee surfaces 4 and 5 converge forward and downward. The downward convergence of lower side surfaces 4 and eliminates pushing ground sideways when the ripper point is in a general working position and is propelled forward through the ground. The general working position is a situation when the centre line 8 has an angle of 300 to the horizontal. The shape of the body of the ripper point in the represented embodiment corresponds to the Aust. Pat.

No.632428.

The represented embodiment of the self-sharpening ripper point has been designed for use with Caterpillar D9, D11 and Komatsu D375 and D475 dozers. Said embodiment shown in Figures 1-6 has a total length of 460mm, Jight of 241mm and the maximum width of 160mm. The length of the leading edge 7 is 30mm and its displacement down from the centre line 8 is 90mm when the centre lii-e 8 is horizontal.

The angle between the upper leading surface 2 and the centre line 8 is 300. The hard insert 6 is 20mm in diameter and 200mm in length. Said hard insert is substantially parallel to the upper leading surface 2 and I positioned at a distance of 5mm from said surface.

The represented embodiment of ripper point shown in figures 1-6 is designed for application without preliminary blasting in a wide variety of hard and highly abrasive ground such as hard cemented hardpan and hard bauxitic caprock with iron content of up to 40%. However, for 20 ripping of iron ore, preliminary blasting will probably be needed on most occasions.

The wear of the hard insert 6 is equilibrated with the wear of the frontal parts of surrounding ripper point's body. Even after a prolonged ripping the hard insert 6 is only marginally protruding from the body 1. As a result, the ripper point remains sharp despite its wear.

Equilibration of wear of the insert and frontal parts of surrounding body 1 is also needed to prevent undermining of said insert by wear of lower surface 3 of the body i.

Such undermining can cause excessive protruding of the insert 6 and its subsequent breakage. Equilibration of wear of the hard insert 6 and frontal parts of surrounding body 1 is easy to achieve using two general methods: 1. By changing of the angle between the axis of the hard insert 6 and the centre line 8. The greater is this 0:40 l ~angle, the better is protection of the lower surfaces against wear and the smaller is the protruding of the hard insert 6. If the angle between the axis of the .00 hard insert 6 and the centre line 8 needs to be steeper than the designed angle between the upper .:so leading surface 2 and the centre line 8, the last angle should be increased to provide a sufficient space for the hard insert 6.

20 2. By changing of cross-section and/or mechanical properties of the hard insert 6. The thicker and harder is the insert 6, the smaller is its wear. In general, very hard ground require harder and thicker inserts.

In Alcoa of Australia Limited, field tests with a prototype of the represented embodiment of the selfsharpening ripper point were performed for fragmentation of hard bauxitic caprock with iron content of up to 40% and enclosed quartz veins. In Water Au'-hority of Western Australia these ripper points were used for ripping hard cemented hardpan. The performed tests showed that during prolonged ripping, the hard insert 6 was only marginally protruding of the body and the ripper point remained sharp.

The tests performed in Alcoa showed an average increase in productivity of ripping by 11% and four folded resistance to wear in comparison with prior art ripper points. In tests by Water Authority of the increase in productivity was 20% and resistance to wear increased times.

Finely, it should be noted that the self-sharpening ripper point can also be used for other applications such as in scrapers, dredges, excavators, rotary bucket and multibucket excavators. All such variations and modifications are to be considered within the scope of the invention, the nature of which is to be determined from the foregoing description and the appended claims.

oooo*

Claims

3. A ripper point according to claim 1 or 2, wherein during prolonged ripping wear of hard insert and frontal parts of ripper points body are substantially equilibrated providing self-sharpening of said ripper point. O0O6 '646 20 4. A ripper point according to claim 1 wherein during 00. "prolonged ripping substantial equilibration of wear of hard insert and frontal parts of ripper points body is achieved by selection of the angle between the hard insert and the lower leading surface of said ripper point. A ripper point according to claim 1 or 2, wherein during prolonged ripping substantial equilibration of wear of hard insert and frontal parts of ripper points body is achieved by selection of dimensions of said hard insert. 13
6. A ripper point according to claim 1 or 2, wherein during prolonged ripping substantial equilibration of wear of hard insert and frontal parts of ripper points body is achieved by selection of mechanical properties of said hard insert. Natural Resources Engineering Pty Ltd Eugene Tsykin, Managing Director. Date ABSTRACT The disclosed invention relates to a ripper point for ground ripping. Self-sharpening ripper point comprises a body 1 with a leading edge 7 positioned substantially below the centre line 8 and a hard insert 6 fixed inside the body close to the leading edge 7, perpendicular to it, wherein the angle between the axis of the insert 6 and the upper leading surface 2 is smaller than the angle between the said axis and the lower leading surface 3. Durinq prolonged ripping self-sharpening is achieved by equilibration of wear of hard insert 6 and the frontal parts of body 1. Said equilibrium is achieved by selection of position, dimensions and mechanical properties of the hard insert 6. Utilisation of a hard insert 6 increases durability of the device and makes it self-sharpening which substantially increases productivity of ripping. see* *o*