Abstract:
The present invention relates to improvements to ripper boots of the type adapted to be mounted to a bulldozer tyne for use in cleaving through hard ground. The ripper boot embodied in the present invention has particular application in opal mining where sometimes extremely hard ground is to be penetrated and ripped. The ripper boot includes a replaceable ripping tooth which is secured within the boot by way of an interference fit so that during use, it does not rotate. The interference fit prevents particular matter from entering between the walls of the tooth and the associated socket. In further forms of the invention, the replaceable ripping tooth is angled upwardly with respect to the carrier so that the angle of attack of the ripping tooth is raised so that it is almost parallel with the ground. The ripper boot provides a number of benefits including improved cleaving effect, reduced chatter and drag, reduced wear and tear, and reduced load on associated machinery.

Description:
[0001]    The present invention relates to an improved ripper boot and, in particular, to a ripper boot for use in a range of applications involving the ripping or cleaving of hard material. The preferred application of the present invention is in opal mining where hard ground is to be penetrated in an attempt to locate opal. 
       BACKGROUND OF THE INVENTION 
       [0002]    Ripper boots are typically used where extremely hard rock or compacted soil is encountered and is required to be penetrated and ripped in an attempt to locate and extract precious stones such as opal. The ripper boot includes a carrier which is typically secured to a bulldozer tyne and a ripping tooth section secured to the nose of the carrier to rip through rock, typically to a depth of approximately 300 mm at a time. In the case of opal mining, the loosened rock is then pushed away, while spotters check for signs of opal. The ripping tooth can also be replaceable. The present inventor has identified some problems with such conventional ripper boots. 
         [0003]    Firstly, some replaceable ripping tooth sections are secured to the boot in a rotatable manner. The problem with having a rotatable ripping tooth is that during operation, ground up rock is able to enter into the area between the shaft of the ripping tooth and the ripper boot body. This causes considerable wear and tear when the shaft rotates which may eventually lead to metal fatigue and fracture under extreme loads. A further problem is that the ripping tooth tends to move and chatter during operation which is also undesirable. Further still, where clay fines and other similar material build up in the area surrounding the ripping tooth shaft, the tooth becomes almost impossible to remove. Existing ripper boots having rotatable teeth are also expensive to manufacture, and their use is limited to only a small range of applications. 
         [0004]    The present inventor has further discovered that the “angle of attack” is extremely important in ripping operations, that is, the angle at which the ripping boot rips through the ground. In conventional ripping operations, the angle of attack is typically governed by the angle at which the end of the bulldozer tyne extends because it is the tyne that carries the ripper boot. The position of the bulldozer tyne is adjustable, however, its movement is restricted and often a desired angle of attack is not attainable. 
         [0005]    When the tooth is ripping at too steep an angle, that is, when the angle between the longitudinal axis of the ripping tooth and the ground surface is too great, the ripper boot will begin to chatter which may result in increased wear and tear on the ripping tooth, metal fatigue and eventual fracture in the ripping tooth. In such circumstances, the load on the bulldozer is also increased which leads to increased fuel consumption. The nose of the ripping tooth tip may also drag when the angle is too steep, and the ripping tooth is prone to being ripped out. In general, where the angle of attack is not correct, the required cleaving effect of the boot is reduced. In fact, it has been found that very small variations in ripping tooth angle can have major effects on the effectiveness of the ripping operation. 
         [0006]    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 
       [0007]    Therefore in one form of the invention there is proposed a ripper boot of the type adapted to be mounted to a shank of a bulldozer or like equipment, said ripper boot characterised by: 
         [0000]    a carrier means adapted to be connected to said shank;
 
a tooth housing means including a female socket;
 
a ripping tooth including a shaft portion and a head portion, said shaft portion being correspondingly shaped with said female socket for removable engagement therewith.
 
         [0008]    Preferably the shaft portion of the ripping tooth is tapered to enable engagement with the correspondingly shaped female socket by way of an interference fit. 
         [0009]    In preference the taper on the shaft portion is such that that a free end thereof has a smaller cross-sectional size to that of the opposed end which is integral with the ripping tooth head portion. 
         [0010]    Preferably the shaft portion of the ripping tooth and female socket are of a square cross-section including slightly rounded edges. Alternatively, the cross-section could be circular. 
         [0011]    Preferably the carrier means, tooth housing means, and female socket extend along the same longitudinal axis. 
         [0012]    In preference the shaft portion of the ripping tooth and the carrier means include transverse channels extending therethrough which become co-axially aligned when the shaft portion of the ripping tooth is secured within the female socket, to thereby allow for insertion of a retaining means. 
         [0013]    Preferably the head portion of the ripping tooth includes an outwardly extending shoulder adapted to facilitate removal of the ripping tooth from within the female socket. 
         [0014]    In preference said tooth housing means includes an ejection hole which extends from an exterior of the boot to said female socket so that said tooth may be ejected from said chamber. 
         [0015]    Preferably at least part of the ripping tooth head portion is constructed from high tensile material such as tungsten metal. 
         [0016]    In a further form of the invention there is proposed a ripper boot of the type adapted to be mounted to a shank of a bulldozer or like equipment, said ripper boot including: 
         [0000]    a carrier means adapted to be connected to said shank, said carrier means including a longitudinal axis; and
 
a ripping tooth removably associated with said carrier means such that said ripping tooth extends at a predetermined angle relative to said longitudinal axis.
 
         [0017]    Preferably said ripper boot is configured so that during use, the ripping tooth extends upwardly from said longitudinal axis to thereby become aligned approximately parallel with a ground surface. 
         [0018]    Preferably said predetermined angle is between zero and ninety degrees from the longitudinal axis of the carrier means. 
         [0019]    In preference said predetermined angle is between zero and ten degrees from the longitudinal axis of the carrier means. 
         [0020]    Advantageously said predetermined angle is six degrees from the longitudinal axis of the carrier means. 
         [0021]    Thus, this further form of the invention provides a ripper boot whereby the ripping tooth is angled upwardly with respect to the ripper boot carrier so that the angle of attack of the ripping tooth is raised and becomes almost parallel with the ground. In altering the angle of attack in this way, it has been found that the cleaving effect of the boot is increased, chatter and drag of the boot through the ground is reduced which results in less wear and tear and less likelihood of the tooth being ripped out, as well as decreased load on the bulldozer which also reduces fuel consumption. 
         [0022]    Preferably said ripper boot further includes a tooth mounting portion associated with said carrier means, said tooth mounting portion configured to removably house said ripping tooth so that it extends at said predetermined angle relative to said longitudinal axis. 
         [0023]    In preference said tooth mounting portion is in the form of a solid member which is integrally formed with said carrier means but which extends at said predetermined angle therefrom. 
         [0024]    Preferably said tooth mounting portion includes a longitudinal axis and a female socket aligned therealong, said female socket adapted to receive a shaft portion associated with said ripping tooth. 
         [0025]    Alternatively said tooth mounting portion is in the form of a solid member which is integrally formed with said carrier means and extends along the same longitudinal axis, said solid member including a female socket which extends at said predetermined angle relative to the longitudinal axis for receiving a shaft portion associated with said ripping tooth. 
         [0026]    Preferably said shaft portion is adapted to be fixedly supported within the female socket by way of an interference fit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    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: 
           [0028]      FIG. 1  illustrates a rear perspective view of an improved ripper boot in accordance with a first aspect of the present invention; 
           [0029]      FIG. 2  illustrates a front perspective view of the improved ripper boot of  FIG. 1 ; 
           [0030]      FIG. 3  illustrates a cross-sectional side view of the improved ripper boot of  FIG. 1 ; 
           [0031]      FIG. 4  illustrates a cross-sectional top view of the improved ripper boot of  FIG. 1 ; 
           [0032]      FIG. 5  illustrates an exploded, partially cross-sectional top view of the improved ripper boot of  FIG. 1 ; 
           [0033]      FIG. 6  illustrates a cross-sectional side view of an improved ripper boot including a retaining pin; 
           [0034]      FIG. 7  illustrates a cross-sectional top view of an improved ripper boot including a retaining pin; 
           [0035]      FIG. 8  illustrates a cross-sectional top view of an improved ripper boot in accordance with a second aspect of the present invention; 
           [0036]      FIG. 9  illustrates a cross-sectional side view of the improved ripper boot of  FIG. 8 ; 
           [0037]      FIG. 10  illustrates a schematic side view of the improved ripper boot of  FIG. 8  when the boot is connected to a bulldozer tyne, and shown in broken lines is a conventional ripper boot arrangement; 
           [0038]      FIG. 11  illustrates a cross-sectional top view of an improved ripper boot in accordance with a third aspect of the present invention; 
           [0039]      FIG. 12  illustrates a cross-sectional side view of the improved ripper boot of  FIG. 11 ; and 
           [0040]      FIG. 13  illustrates a bulldozer including an improved ripper boot mounted to the bulldozer tyne in accordance with all aspects of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]    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. 
         [0042]    The present invention relates to an improved ripper boot according to three different embodiments  10   a ,  10   b  and  10   c . The ripper boot  10   a  is illustrated in  FIGS. 1-7 , ripper boot  10   b  in  FIGS. 8-10 , and ripper boot  10   c  in  FIGS. 11-12 .  FIG. 13  illustrates a bulldozer  12  to which any one of the ripper boots could be attached. For the purpose of brevity, the first ripper boot  10   a  will be described in full detail and any like parts found in the other ripper boots will not be described again and will be referred to using like numbers. 
         [0043]      FIGS. 1-5  illustrate the ripper boot  10   a  of the present invention which includes a carrier  14  and a replaceable ripping tooth  16 . In operation, the carrier  14  is placed over and conformed to fit with a ripper boot tyne  18  of a bulldozer  12  or other earth moving machinery, as is shown in  FIG. 13 . The various components of the bulldozer  12  are not described herein because bulldozers such as these are well known in the art, and apart from the ripper boot tyne  18 , the remaining components do not perform any function insofar as the present invention is concerned. 
         [0044]    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  24 , is designed to attach the carrier  14  of the ripper boot  10   a  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. 
         [0045]    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 mechanism to some degree. Primarily, the solid portion  26  provides a female socket or bore  28  adapted to fixedly house a replaceable ripping tooth  16 . The bore  28  is of a square cross-section and includes longitudinal walls that taper inwardly such that the cross-sectional size of the bore  28  adjacent the hollow portion  22  is less than that adjacent the tooth end. All four edges of the socket  28  are rounded off for additional strength. 
         [0046]    The replaceable ripping tooth  16  is made up of a head portion  30  and a shaft  32 . The shaft  32  of the replaceable ripping tooth  14  is correspondingly shaped with the female socket  28  of the carrier  12 , that is, it too includes tapered walls and is of a square cross-sectional shape having rounded corners. This allows the shaft  32  to be fixedly secured within the female socket  28  by way of an interference fit. As those skilled in the art would realise, an interference fit is extremely strong and will not permit any rotation at all of the replaceable ripping tooth  16  and ensures that no particles enter between the wall of the shaft  32  and the abutting wall of the female socket  28 . In preference, the socket  28  is cast so as to ensure that its dimensions correspond with those of the shaft  32 . 
         [0047]    Once the tooth is fixed within the socket  28 , the head portion  30  extends longitudinally outwards from the solid portion  26  of the boot and therefore tapers at substantially the same angle as the solid portion  26 . The head portion  30  of the tooth is designed 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. Mounted to the end of the replaceable ripping tooth  16  is a pointed tip  34  which can be made of high tensile strength material, such as tungsten for example. The tip  34  may simply be welded to the replaceable ripping tooth  16 . A high tensile tip  34  ensures that even the hardest rock may be penetrated and that problems associated with existing ripper boot tips which become easily worn are minimised. 
         [0048]    In attaching the replaceable ripping tooth  16  to the carrier  14  as described above, a number of benefits are provided. 
         [0049]    Firstly, chatter is reduced during operation because the tooth  16  is fixed, and wear and tear on the tooth  16  is also reduced in that ground dirt can no longer enter the gap between the tooth shaft  32  and the female socket  28 . This is a major problem with rotatable teeth in that particles abrade against the respective surfaces during operation and lead to metal fatigue and eventual failure in the tooth  16 . 
         [0050]    Secondly, the interference fit allows for easier removal of the ripping tooth  16  in that clay fines are no longer able to build up around the ripping tooth shaft  32 . As mentioned in the preamble of the invention, this often prevents the tooth from being able to be removed. In this case, simply breaking the taper will cause the tooth to fall out, and a means of achieving this will be described shortly. 
         [0051]    Thirdly, the ripper boot 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. Such boots are also less expensive to manufacture. 
         [0052]    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 . Illustrated in  FIGS. 6-7  is a ripper boot  10  including such a retaining pin  36 . The tooth  16  includes a groove  38  extending transversely across a lower side thereof such that when it is fully inserted into socket  28 , the groove  38  becomes co-axially aligned with an aperture  40  which extends transversely through the solid portion  26  of the carrier  12 . Once aligned, the retaining pin  36  may simply be inserted through the aligned holes to lock the tooth in place. 
         [0053]    It is envisaged that an interference fit is adequate in maintaining the tooth fixed within the socket, but a secondary locking means such as this 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. All other aspects of the ripper boot in  FIGS. 6-7  are identical to those in the previous figures. 
         [0054]    Removal of the ripping tooth  16  from the carrier  12  may be accomplished in a number of ways. The tooth  16  includes a protrusion or shoulder  42  extending outwards from the head portion  30  of the tooth  16  which is adapted to facilitate removal of the tooth  16 . The shoulder  42  may be engaged by an appropriate tool and pried off when the tooth has become worn following prolonged use. 
         [0055]    Alternatively, the ripping tooth  16  may be removed by way of insertion of a push rod (not shown) or other similar object through an ejection hole  44  extending from the hollow portion  22  of the carrier  14  to the female socket  28 . As those skilled in the art would appreciate, when the ripping tooth  16  is locked within the female socket  28 , such action will force the ripping tooth  16  from the female socket  28 . 
         [0056]    It is to be understood that the configuration of the ripping tooth  16  may vary. In this case, the pointed tip  34  includes a double inward taper before terminating into a point. This feature, combined with the high tensile properties of the tip  34 , ensures that even the hardest rock may be penetrated with minimal slip and that problems associated with existing ripper boot tips which become easily worn are alleviated. But other types of tips may be used such as single taper tips, or curved tips. Further, the cross-sectional shape of the ripping tooth shaft  32  and carrier bore  28  need not be square but may be any other shape such as triangular or circular, provided an interference fit is still achievable. 
         [0057]    It is to be further understood that the configuration of the female socket  28  in the area adjacent the end of the ripping tooth shaft  32  may also vary. For example, in the drawings there is shown a clearance  46  between the end of the shaft  32  and the end of the bore  28 , as well as the ejection hole  44 . Another variation could be for the tapered walls of the bore  28  to simply extend the entire distance through to the hollow portion  22  as is the case in the second and third embodiments of the invention. A still further variation may be where there is no gap at all between the hollow portion  22  of the boot  12  and the bore  28 . 
         [0058]    In using a replaceable ripping tooth that is adapted to be fixed during operation, such as those disclosed in the present invention, it has been found that previously encountered problems relating to ripper boot chatter, wear and tear on the ripping tooth, ripping tooth fracture, and other associated problems have been significantly reduced. More specifically, such ripper boots have resulted in benefits such as fuel savings of up to 10% due to reduced load on the bulldozer, savings of up to 50% in working time because of the ability to rip rock precisely, and total cost savings including manufacturing cost of up 10-20%. 
         [0059]    The second embodiment of the invention is illustrated in  FIGS. 8-9  and relates to a ripper boot  10   b  which has the same interference fit tooth  16  as described above, but which includes an alternate angle of attack. 
         [0060]    This angle of attack concept can be clearly appreciated in  FIG. 10  which illustrates the ripper boot  10   b  of the present invention, as well as a conventional ripper boot  48  in broken lines for the purpose of comparison. Those skilled in the art will appreciate that where the solid portion of the conventional ripper boot  48  extends in the same longitudinal direction as that of the carrier  14 , the solid portion  26  of the ripper boot  10   b  is angled upwardly with respect to the carrier  14  when fully assembled. In having an upwardly angled solid portion  26 , those skilled in the art will appreciate that the ripping tooth  16  once inserted will also be angled with respect to the carrier  14 . 
         [0061]    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. 
         [0062]    Existing ripper boots may be modified to include the features of ripper boot  10   b . For example, a saw cut may be made at the junction between the carrier  14  and the solid portion  26  of the ripper boot  10   a  of the first embodiment. The cut would be made at a desired angle relative to the longitudinal axis of the carrier. Then, when a solid portion is welded to the angled end of the carrier  14 , those skilled in the art will appreciate that it will extend at an angle corresponding with the angle of the cut. 
         [0063]    It has been found that when the tooth is positioned at this angle, the boot cleaves through the ground more efficiently than hitherto known ripper boot arrangements resulting in similar benefits to those mentioned above including 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  extends with respect to the carrier  14  may be made to vary depending on the required operation. 
         [0064]      FIGS. 11-12  illustrate a ripper boot  10   c  according to a third aspect of the present invention. The ripper boot  10   c  differs from the ripper boot  10   b  slightly in that rather than the solid portion  26  of the boot being angled, it extends longitudinally with respect to the carrier  12  as was the case in the ripper boot  10   a  of the first embodiment. In this case though, a raised angle of attack is achieved by having a female socket  28  cast at a predetermined angle through the solid portion  26  of the boot so that the ripping tooth  16  may extend outwards therefrom at that angle. Again, for the purpose of brevity, the same reference numbers have been used. 
         [0065]    The angle is such that in use, the ripping tooth  16  will extend slightly upwardly so as to become more parallel with the ground surface. The benefits of having a raised angle of attack as provided by this third embodiment of the invention have been described above. 
         [0066]    Although not illustrated, it is to be understood that this ripper boot  10   c  could also include a retaining pin for additional support as described previously. 
         [0067]    Ripper boot  10   a  could also be modified to include an angled ripping tooth according to this third embodiment by making a straight saw cut at the junction between the carrier  12  and the solid portion  26  and simply replacing the solid portion with one that has an angled bore cast there through. 
         [0068]    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. 
         [0069]    In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprising” is used in the sense of “including”, i.e. the features specified may be associated with further features in various embodiments of the invention.