The present invention relates to an improved ripper boot and, in particular, to a ripper boot having a male carrier portion for engaging a replaceable female tooth or cap having a high tensile tip. The ripper boot of the present invention is suitable for use in a range of applications involving the ripping or cleaving of extremely hard material.

BACKGROUND OF THE INVENTION

The present inventor is the owner of a number of co-pending patent applications relating to ripper boot improvements, including Australian Letters Patent No. 2006284527 relating to a ripper boot having a replaceable ripping tooth. The ripping tooth includes a shank having tapered sides adapted to be press fit into a correspondingly shaped cavity in the boot so that it is fixed during operation for improved performance and reduced wear and tear.

This invention is useful in any application where extremely hard and abrasive rock is to be excavated, for example, in the extraction of precious stones such as opal typically achieved using a standard bulldozer ripper boot, or in heavier duty operations which require excavators and the like. In each of these environments, the ripper boot teeth, loader bucket teeth, etc, need to be strong and wear resistant enough to work the hard rock. Conventional ripper boots tend to break, and apply extremely high loads on machinery.

Conventional ripper boots consist of predominantly two sections, a carrier section for attachment to machinery, for example, to a bulldozer tyne or loader bucket shank, and a tooth section which is typically integrally associated with the carrier section via a weld. In the applicant's abovementioned patent, it is proposed that the tooth section be made replaceable. More particularly, the proposed tooth section includes a shank having tapered sides being fixable within a correspondingly shaped cavity associated with the carrier section by way of an interference fit.

Although very successful in its operation, the present Applicant has recognised the need for a still further improved replaceable tooth. There is a need for a boot and replaceable tooth combination which addresses issues such as particles becoming clogged in the space between the tooth shank and the carrier cavity, and difficulties in removing the replaceable tooth after use. One reason this occurs is that the gap between the tooth head portion and the carrier section is adjacent the tip of the boot and is inclined to receive particles therein. In the case of the Applicant's prior art apparatus, because this gap is "upstream" of the taper locked walls, as the ripper boot moves through ground particles are inclined to enter between the walls via the gap. The result is that the tooth can become caked inside the socket to an extent where it can no longer be removed.

It is therefore an object of the present invention to overcome at least some of the aforementioned problems or to provide the public with a useful alternative.

SUMMARY OF THE INVENTION

Therefore in one form of the invention there is proposed a ripper boot characterised by:

a carrier adapted for connection to a shank of a vehicle;

a locking tapered male projection associated with a tip of said carrier;

a replaceable ripping cap including a substantially conical outer shape terminating in a tip of high tensile material, said cap further including a locking tapered bore to mate with said locking tapered male projection such that said cap is non-rotatably secured on said ripper boot carrier by way of locking interference fit such that during use said replaceable ripping cap does not rotate and said locking interference fit prevents particulate matter from entering between walls of said cap and said male projection.

Preferably said locking tapered male projection is inwardly tapered such that its cross sectional dimension is less at the tip of the carrier, said locking tapered bore having a corresponding inward taper. In preference said cap is removable from the male projection when said taper lock is broken.

In preference the cross section of the male projection and the cap bore is square.

Alternatively the cross section of the male projection and the cap bore is circular.

Preferably the carrier includes a central longitudinal axis. In preference said male projection and engaged cap extend along said longitudinal axis such that the angle of attack is greater than the angle of the surface being worked.

Alternatively said male projection is constructed to extend at an angle upwards from said carrier longitudinal axis such that the angle of attack of the engaged cap is substantially parallel with the angle of the surface being worked.

Preferably said angle of attack is between zero and ninety degrees upwards from the longitudinal axis of the carrier.

In preference said angle of attack is between zero and ten degrees upwards from the longitudinal axis of the carrier. Advantageously, and when applied to most standard dozers, the angle of attack should be approximately six degrees upwards from the longitudinal axis of the carrier.

Preferably the male projection and the cap include transverse channels extending there through which become co-axially aligned when the projection is engaged within said cap bore, to allow for insertion of a retaining pin. In preference said high tensile tip is constructed at least partially of tungsten metal.

In a further form of the invention said carrier includes two or more male projections adapted to engage two or more removeable caps.

In a still further form of the invention there is proposed a ripper boot characterised by:

a carrier including a male projection at a working end thereof;

a replaceable ripping cap including an associated socket;

said replaceable ripping cap being secured to said carrier by way of an interference fit so that during use said replaceable ripping cap does not rotate;

said interference fit prevents particulate matter from entering between walls of said cap and said associated socket;

said male projection has a tapered wall;

said cap has a tapered socket to mate with said tapered wall; and wherein:

said cap has a substantially conical outer shape and terminates in a tip constructed at least partially of high tensile material;

said cap and said carrier engage by a mating relationship between said socket and said correspondingly shaped male projection, said socket and male projection being inwardly tapered to thereby establish a taper lock between the carrier and cap, said cap being removable from the carrier when said taper lock is broken.

Preferably said ripper boot further includes retaining means for retaining said cap on said carrier. In preference said retaining means is in the form of a retaining pin, the carrier projection and cap including transverse channels extending there through which become co- axially aligned when the cap is fully engaged on said male projection, to allow for insertion of said retaining pin.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several implementations of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings:

Figure 1 illustrates a rear view of a ripper boot in accordance with the present invention;

Figure 2 illustrates a front view of the ripper boot of Figure 1 ;

Figure 3 illustrates a top view of the ripper boot of Figure 1 ;

Figure 4 illustrates a side view of the ripper boot of Figure 1 ;

Figure 5 illustrates a side cross-sectional view of the ripper boot of Figure 1; Figure 6 illustrates an exploded perspective view of the ripper boot of Figure 1 ;

Figure 7 illustrates a cross-sectional view of a ripper boot in accordance with a second embodiment of the present invention;

Figure 8 illustrates an exploded perspective view of the ripper boot of Figure 7;

Figure 9 illustrates a cross-sectional view of a ripper boot in accordance with a third embodiment of the present invention; and

Figure 10 illustrates an exploded perspective view of the ripper boot of Figure 9. DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts.

The present invention relates to an improved ripper boot according to three different embodiments 10a, 10b and 10c. The ripper boot 10a is illustrated in Figures 1-6, ripper boot 10b in Figures 7-8, and ripper boot 10c in Figures 9-10. For the purpose of brevity, the first ripper boot 10a will be described in full detail and any like parts found in the other embodiments will not be described again and will be referred to using like numbers.

Figures 1-6 illustrate the ripper boot 10a of the present invention which includes a carrier 14 and a replaceable ripping tooth or cap 16. In operation, the carrier 14 is placed over and conformed to fit with a ripper boot tyne of a bulldozer (not shown) or other earth moving machinery.

The carrier 14 is held in place by utilisation of a pair of oppositely positioned retaining holes 20 located in the rear hollow portion 22 of the carrier 14 which, in conjunction with a retaining pin (not shown), is designed to attach the carrier 14 of the ripper boot 10a to the available tyne 18. It is to be understood that the carrier 14 may be conformed to fit any available ripper boot shank, and that any desired attachment means other than the retaining pin 24 and oppositely positioned retaining holes 20 may be used.

The ripper boot carrier 14 also includes a substantially solid portion 26 at its front. This solid portion 26 provides mass and assists in the ripping process to some degree, and also provides a male projection 28 which in the embodiment shown is shaped substantially like a four-sided pyramid having a sawn-off apex. The base of the male projection 28 is of a lesser dimension to that of the solid portion, and so an inward shoulder is defined there around. The inward shoulder includes a kink on two opposed sides, however, this is not essential to achieving engagement between the two members but rather for facilitating assembly as will be explained in more detail below.

The replaceable ripping tooth 16 is made up of a head portion 30 and a female body 32. Primarily, the female body 32 provides a female socket or bore 34. The bore 34 includes longitudinal walls that taper outwardly and which are conformed to fit over the male projection 28 of the carrier 14.

The projection 28 of the carrier 14 is thus correspondingly shaped with the female socket 34 of the tooth 16, and allows the projection 28 to be fixedly secured within the female socket 34 by way of an interference fit, otherwise known as a taper lock. As those skilled in the art would realise, an interference fit is extremely strong and will not permit any rotation of the replaceable ripping tooth 16, even if say the side walls had a circular cross section. In preference, the socket 34 is cast so as to ensure that its internal dimensions correspond with those of the male projection 28.

One of the benefits of the present invention is that the taper locked walls are less inclined to receive small particles of rock, including clay fines, which are a known cause of irrevocably locking the male and female portions together. This is because the engaging walls are located "upstream" of the gap between the carrier and the tooth sections, that is, inside the ripping tooth as opposed to inside the carrier 14. Because of the forward cleaving action of the boot 10, and the configuration of the tooth 16, it is unlikely that fines will enter the gap between the base of the tooth body 32 and the solid portion 26 of the carrier 14 and then travel forwards between the taper locked side walls. Thus, even after extensive use, the tooth 16 should still be easily removable and replaceable, without having to remove the carrier 14 from the dozer.

Once the tooth is fixed onto the projection 28, the head portion 30 extends longitudinally outwards from the boot. The head portion 30 of the tooth is designed as a conical structure which does not to extend too far outwards from the carrier 14 so as to ensure it is not damaged or broken off during the ripping process. The head portion 30 can be made of high tensile strength material, such as tungsten for example. A high tensile tip ensures that even the hardest rock may be penetrated and that problems associated with existing ripper boot tips which become easily worn are minimised.

It is to be understood that the ripper boot 10 of the present invention is not limited in its use and may be used in association with a wide variety of machinery including small to large bulldozer rippers, end cutting bits on dozer blades, dragline buckets, bucket dredges, excavators, and loader bucket teeth. In some of these larger operations, the present invention becomes particularly effective because of the labour and cost involved in the need to replace such heavy pieces of equipment from the machinery, and instead just having to replace an easily removeable, lighter weight cap.

In cases where the tooth may become prone to rust, for example in

applications where the tolerances between the tooth and the projection are not required to be so tight, it is envisaged that the projection 26 and/or tooth 16 can be coated with a suitable rust-proof coating. In order to ensure that the replaceable ripping tooth 16 is always fixed within the carrier 14 during use, a secondary locking means may also be used, preferably in the form of a retaining pin 36. The ripper boot 10 embodied in Figures 1-6 includes such a retaining pin 36. The projection 28 includes a groove 38 extending transversely across a lower side thereof such that when it is fully inserted into socket 34, the groove 38 becomes co-axially aligned with an aperture 40 which extends transversely through the body 32 of the tooth 16. Once aligned, the retaining pin 36 may simply be inserted through the aligned holes to lock the tooth in place.

It is to be understood that the groove 38 need not extend all the way through the projection, but may for example only extend halfway, in which case the locking pin 36 would be half of the length shown, and an aperture 40 would only need to be present through one face of the tooth body 32.

It is envisaged that an interference fit is adequate in maintaining the tooth fixed within the socket, but a secondary locking means such as the locking pin may be used if required. The pin may be of the compressible type whereby prior to insertion, its cross section must be compressed so that following insertion it expands to provide a tighter fit. As mentioned earlier, the carrier includes a shoulder with a kink on only two opposed walls adapted to act as a locating means and receive correspondingly shaped walls of the cap. The skilled addressee would realise that this will assist the assembler in placing the cap over the male projection in the correct orientation and ensuring the apertures line up. In the embodiment shown, the apertures 38 in the cap are in the extended walls which are received in the kinks. It is to be understood that the present invention does not require any means of orientation assistance for placement of the cap over the male projection, and that if one is used, it need not necessarily be limited to that shown in the embodiment and described herein.

Removal of the ripping tooth 16 from the carrier 12 may be accomplished by simply breaking the taper lock between the engaging walls using any suitable prying tool.

It is to be understood that the configuration of the ripping tooth 16 may vary. In this case, the head 30 is a conical head, however, it could equally well be a conical- type head having a double inward taper rather than just a single taper angle.

Furthermore, as mentioned earlier, the cross-sectional shape of the projection 28 and socket 34 need not be square but may be any other shape such as triangular or circular, provided an interference fit is still achievable.

The second embodiment of the invention is illustrated in Figures 7-8 and relates to a ripper boot 10b which has the same interference fit tooth 16 as described above, but which includes an alternate angle of attack. In having an upwardly angled solid portion 26 and projection 28, those skilled in the art will appreciate that the ripping tooth 16 once fitted onto the projection will also be angled with respect to the carrier 14.

The angle of the solid portion 26 is shown in the drawings to be quite substantial for the purpose of clarity, however, through experimentation it has been found that an angle of approximately 6 degrees from the longitudinal axis of the carrier body is optimal. At this angle, the outer surface of the ripping tooth becomes aligned approximately parallel with the layers of rock being cleaved. These layers are typically, but not always, parallel with the ground surface. Existing ripper boots, including ripper boot 10a, may be modified to include the features of ripper boot 10b. It has been found that when the tooth is positioned at this angle, the boot may cleave through the ground more efficiently than hitherto known ripper boot arrangements resulting in benefits such as reduced chatter, reduced wear and tear on the tooth, and reduced load on the bulldozer. It is to be understood that the angle at which the solid portion 26 and projection 28 extend with respect to the carrier 14 may be made to vary depending on the required operation.

A raised angle of attack could equally well be achieved by having a solid portion 26 and projection 28 extending longitudinally with respect to the carrier 12, as was the case in the ripper boot 10a of the first embodiment, but with socket 34 cast at a predetermined angle inside the tooth 16 so that the ripping tooth 16 may extend outwards therefrom at that angle.

Figures 9-10 illustrate a ripper boot 10c according to a third aspect of the invention. Rather than having a single socket arrangement, the tooth 50 includes two sockets for receiving two projections of the carrier 14. There are two head portions 52 and 54 associated with the tooth 50. Such a configuration may be suitable in a number of different applications including in excavator loader buckets which require a plurality of teeth for their operation. For example, a single loader bucket may include a single shank portion (not shown) for attachment thereto of a single carrier section having a plurality of associated tooth sections. As already mentioned, the present invention is not intended to be limited to any one of these configurations.

Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred

embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.