Abstract:
A trench excavating machine includes an excavating wheel on which are mounted spaced apart peripheral plates equipped with ripping teeth and spades. The ripping teeth are angled outward from the plates at an acute angle directed in the direction of rotation of the cutting wheel to attack the leading edge of a trench being excavated. Ripping teeth and spades are arranged at varying spacing on succeeding plates about the centerline of the cutting wheel. A transverse conveyor located within the circumference of the cutting wheel transports spoil to the side of the cutting wheel. A spoil deflector removes spoil adhered to the inside of the cutting wheel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from copending provisional patent application entitled “Excavating Machine for Rocky and Other Soils,” Ser. No. 60/634,323 filed Dec. 8, 2004. The disclosure of provisional patent application Ser. No. 60/634,323 is hereby incorporated in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The invention relates generally to excavating machines of the type having a device for cutting the earth including bucket wheel trenchers, chain bar trenchers, trencher or trenchless plows and hoes, vibratory plows, disc wheel cutters, drum cutters, etc., and more particularly to a cutting plate carried on the trenching wheel or chain for breaking through rocky soils.  
         [0003]     Excavating machines are well known for use in the cutting of an open trench having either vertical or sloped walls for the purposes of land drainage and irrigation including agricultural tiling, as well as the installation of utilities such as cable lines, pipelines, water lines, sewer lines, etc. These excavating machines are often of a vehicular type being self-contained and suitably driven for either over-the-road travel or movement during use of the earth cutting device.  
         [0004]     Existing excavating machines usually employ earth cutting buckets or shovels for cutting into the earth and removing spoil from the trench being made but these elements do not function well when rocks within the earth to be trenched are encountered. Circular saws have been utilized for cutting through rocky soils but these machines do not effectively excavate spoil from a trench. In addition, most trenching excavators are mounted on crawler tractors and are of very large mass and cannot be driven on hard surface roadways without damage to the roadway being traversed.  
         [0005]     A need exists for a trench excavator which can penetrate rocky soils, as well as soils which are sandy or otherwise not populated with rocks, while simultaneously effectively removing spoil from the trench.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention provides a wheel excavating machine which includes a series of spaced apart plates mounted on the periphery of the wheel. Each plate is provided with one or more ripping teeth or spikes which extend outward from the plates, with succeeding plates on the wheel having the spikes arranged in a pattern which is offset from the placement of the spikes on the adjacent plates. The spikes are directed outwardly in the direction of rotation of the excavating wheel such that on the spikes are driven against and into the soil wall. In addition, the plates mounted on the periphery of the wheel may contain spade members which extend from a leading edge of each plate and are angled slightly outward from the center of the excavating wheel to claw at softer soils and ground rocks which have first been attacked by the spikes.  
         [0007]     The excavator is equipped with an L-shaped lifting arm to which the excavating wheel assembly is mounted which allows the excavating wheel assembly and associated shoe member to be raised or lowered at the rear of the drive unit or tractor. The L-shaped lifting arm allows downward force to be applied to the wheel assembly. A transverse conveyor is located within the circumference of the wheel such that spoil carried over the top of the wheel may drop on the conveyor and be moved to the side of the trench being excavated. A cleaning member with a cleaning face is located at the top of the digging wheel in such a manner that it removes the spoil which has accumulated in the rim structure of the digging wheel and directs the spoil downwardly onto the conveyor.  
         [0008]     A shoe member follows the trenching wheel through the trench being excavated. The shoe member in cooperation with the L-shaped lifting arm provides a fulcrum for downward force placed on the L-shaped arm by hydraulic cylinders, thereby forcing the excavating wheel into the trench and reducing the mass of the drive tractor needed to hold the wheel in the trench. The drive unit is carried on wheels with tires which permit the machine to be transported under its own drive power on a roadway.  
         [0009]     Accordingly, it is an object of the present invention to provide an excavating machine which can trench through rocky soil as well as through non-rocky soil.  
         [0010]     It is a further object of the present invention to provide an excavating machine which can be operated more efficiently.  
         [0011]     It is also an object of the invention to provide an excavating machine which can be driven at reasonable roadway speeds on hard surface roadways.  
         [0012]     An additional object of the present invention is to provide an excavating machine which efficiently removes spoil from the trench being excavated.  
         [0013]     Other features and advantages of the present invention will become apparent upon a review of the following description, drawings and claims. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0014]      FIG. 1  is a front elevational view of an excavating machine in accordance with the present invention with its ground cutting means in a raised position;  
         [0015]      FIG. 2  is a front elevational view of the excavating machine shown in  FIG. 1  with its ground cutting means at ground level;  
         [0016]      FIG. 3  is a front elevational view of the excavating machine shown in  FIG. 1  with its ground cutting means partially below ground level;  
         [0017]      FIG. 4  is a front elevational view of the excavating machine shown in  FIG. 1  with its ground cutting means at the bottom of a trench;  
         [0018]      FIG. 5  is a top perspective view of an L-arm assembly in accordance with the present invention;  
         [0019]      FIG. 6  is a bottom perspective view of the L-arm assembly shown in  FIG. 5 ;  
         [0020]      FIG. 7  is a top perspective view of the L-arm assembly showing a slidable leg member in its extended position;  
         [0021]      FIG. 8  is a top perspective view of the L-arm assembly shown in  FIG. 7  showing the slidable leg member in its retracted position;  
         [0022]      FIG. 9  is a front elevational view of the supporting frame assembly and the wheel assembly of the excavating machine shown in  FIG. 1 ;  
         [0023]      FIG. 10  is an end plan view of the rim assembly of the cutting wheel assembly in section with an engagement plate mounted thereto;  
         [0024]      FIG. 11  is a top perspective view of an exemplary plate member showing the ripping teeth and spades mounted thereto;  
         [0025]      FIG. 12  is a section view of the plate member of  FIG. 11  taken along line  12 - 12  of  FIG. 11 .  
         [0026]      FIGS. 13A and 13B  are diagrammatic views of a series of plate members mounted to the rim structure, shown partly cut away, of the wheel assembly of the excavating machine.  
         [0027]      FIG. 14  is a perspective of a deflecting member of the invention carried on a support member.  
         [0028]      FIG. 15  is a partial cross-sectional elevational view of the wheel assembly shown in  FIG. 9  taken along lines  15 - 15 ;  
         [0029]      FIG. 16  is a front elevational view of an alternative cleaning member and wheel frame assembly in accordance with the present invention;  
         [0030]      FIG. 17  is a top perspective view of a conveyor assembly in accordance with the present invention, with most of the endless conveyor belt removed;  
         [0031]      FIG. 18  is a bottom perspective view of the conveyor assembly shown in  FIG. 17 ;  
         [0032]      FIG. 19  is a cross-sectional view of the endless conveyor belt shown in  FIG. 17  taken along lines  19 - 19 ;  
         [0033]      FIG. 20  is a cross-sectional view of the endless conveyor belt shown in  FIG. 17  taken along lines  20 - 20 ;  
         [0034]      FIG. 21  is a side elevational view of a shoe assembly and an adjustable groover assembly in accordance with the present invention;  
         [0035]      FIG. 22  is a sectional front elevational view of the shoe assembly and the adjustable groover assembly shown in  FIG. 21  taken along lines  22 - 22 ;  
         [0036]      FIG. 23  is a top perspective view taken from the rear of the adjustable groover assembly and a mounting assembly shown in  FIG. 21 ;  
         [0037]      FIG. 24  is a top perspective view taken from the front of the adjustable groover assembly and the mounting assembly shown in  FIG. 21 ;  
         [0038]      FIG. 25  is a top perspective view taken from the rear of the adjustable groover assembly shown in  FIG. 21  in its closed position; and  
         [0039]      FIG. 26  is a top perspective view taken from the rear of the adjustable groover assembly shown in  FIG. 21  in its open position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0040]     This invention discloses an improved excavating machine for cutting a trench through the earth. The invention particularly discloses an improved excavating machine for trenching through rocky soils. Prior improvements to wheel trenchers invented in whole or in part by one of the instant inventors are shown in U.S. Pat. Nos. 4,890,670; 5,873,186; 5,943,798; and 6,055,750; the disclosures of each of which are incorporated herein by this reference.  
         [0041]     Referring to  FIG. 1 , the numeral  30  generally designates the excavating machine of the present invention. The excavating machine  30  includes a power unit vehicle  32  supported by wheels  34 . Pivotally mounted about a horizontal axis  35  on the power unit vehicle  32  is an L-arm assembly  36  which is adapted to be raised and lowered by means of a hydraulic cylinder  38 . Pivotally mounted to the L-arm assembly  36  is earth cutting assembly  40 . The earth cutting assembly  40  of the preferred embodiment comprises a rock wheel trencher assembly  42  and a supporting frame assembly  44 . The supporting frame assembly  44  is pivotally mounted about a horizontal axis  46  as part of a means for controlling the pitch of the earth cutting assembly  40 , and this pivotal movement is controlled by a second hydraulic cylinder  48 . Rotatably mounted to the supporting frame assembly  44  is a wheel assembly  50 . Also mounted to the supporting frame assembly  44  are a conveyor assembly  52  and a shoe assembly  54 .  
         [0042]      FIGS. 1-4  schematically show the excavating machine  30  in its range of positions.  FIG. 1  shows the excavating machine  30  with earth cutting assembly  40  raised to its highest position, when machine  30  is ready for movement to a new site.  FIG. 2  shows the earth cutting assembly  40  lowered to ground level  55 .  FIG. 3  shows the earth cutting assembly  40  partially below ground level  55  as a trench  56  in rocky ground or solid rock  58  is begun.  FIG. 4  shows the earth cutting assembly  40  in a position at the bottom  59  of the trench  56  in the ground  58 .  
         [0043]      FIGS. 5-8  show the L-arm assembly  36  for raising and lowering the earth cutting assembly  40 . The L-arm assembly  36  is located between the power unit vehicle  32  and the earth cutting assembly  40 . The L-arm assembly  36  includes a first arm  60  having a first end  62  and a second end  64  opposite to the first end  62 . The L-arm assembly  36  further includes a second arm  66  integral with and substantially transverse to the first arm  60 . The second arm  66  has a first end  68  integral with the first end  62  of the first arm  60  and a second end  70  opposite to the first end  68  of the second arm  66 . The second end  64  of the first arm  60  includes apertures  72  for receiving a pivot member  74  for pivotal attachment to the power unit vehicle  32 . The second end  70  of the second arm  66  includes an extended lift member  76  having an apertures  78  for receiving a pivot member  80  for pivotal attachment to the supporting frame assembly  44  about horizontal axis  46 . The first arm  60  of the L-arm assembly  36  is longer than the second arm  66  of the L-arm assembly  36 .  
         [0044]     While it is anticipated that the L-arm assembly  36  could comprise one L-arm of solid construction (not shown), the preferred embodiment as shown in  FIGS. 5 and 6  shows an assembly of two separate L-arms  82  spaced apart by tubular support members  84 . In addition,  FIGS. 5 and 6  show that the first arm  60  of each L-arm  82  is comprised of a top plate  86  and first and second side plates  88  and  90 , respectively, the first side plate  88  being substantially parallel with the second side plate  90  with a slight divergence between the first side plate  88  and second side plate  90  from the first end  62  of the first arm  60  to the second end  64  of the first arm  60 . In addition, the second arm  66  of each L-arm  82  is comprised of a rectangular housing  94  with the extended lift members  76  extended from the second end  70  thereof.  
         [0045]     The L-arm assembly  36  also includes means for attachment to the hydraulic cylinder  38  to raise and lower the L-arm assembly  36  in the form of two gusset plates  96  having apertures  98  therein for receiving a pivot member  100  for pivotal attachment to the hydraulic cylinder  38 . It is preferred that these means for attachment to the hydraulic cylinder  38  be proximate to the first end  62  of the first arm  60  of the L-arm assembly  36 .  
         [0046]     In the preferred embodiment wherein the L-arm assembly  36  is made up of two parallel L-arms  82 , one of the parallel second arms  66  includes within its rectangular housing  94  means for extending and retracting the extended lift member  76 . Means for extending and retracting an extended lift member  102  relative to a rigidly connected extended lift member  104  are shown in FIGS.  7  (extended) and  8  (retracted). A telescoping housing  106  is operably attached between a linear actuator  108  (shown uncovered in  FIGS. 1-4 ) and the lift member  102 .  
         [0047]     While the L-arm assembly  36  of the present invention is shown on an excavating machine  30  having a rock wheel trencher assembly  42 , it is to be understood that this L-arm assembly  36  could be incorporated with any type of excavating machine having earth cutting means as original equipment or sold separately as a retrofit part for existing equipment.  
         [0048]      FIG. 9  shows an enlarged elevational view of the supporting frame assembly  44  and the wheel assembly  50  mounted rotatably thereon. A hitch  116  having an aperture  118  therein is included for receiving pivot member  46  for pivotal attachment to the second end  70  of the second arm  66  of the L-arm assembly  36 . In addition to pivotal movement upon extension or retraction of the hydraulic cylinder  48 , when the slidable lift member  102  is extended or retracted relative to the fixed lift member  104  by linear actuator  108 , the supporting frame assembly  44  and the wheel assembly  50  are adjustable from their normal vertical orientation. This is beneficial when a vertical trench is to be dug on uneven ground or when a non-vertical trench is to be dug.  
         [0049]     The supporting frame assembly  44  also includes a flange  122  having an aperture  124  therein for receiving a fastening member  126  for operable attachment to the second hydraulic cylinder  48  for the supporting frame assembly  44 . Accordingly, as the second hydraulic cylinder  48  for the wheel frame assembly  44  is extended and retracted, the pitch of the supporting frame assembly  44  is adjusted up or down in accordance therewith.  
         [0050]     The wheel assembly  50  includes a digging wheel  128  having a rim structure  130  and a series of circumferentially spaced plate members  132  peripherally mounted to the rim structure  130  of the digging wheel  128 . A truck roller assembly  134  is rigidly connected to the supporting frame assembly  44  for adjustment of the digging wheel  128  and to maintain the digging wheel  128  in a desired position. The digging wheel  128  is driven in a counter-clockwise direction as illustrated in  FIGS. 1-4 , by a drive mechanism  136 . As the digging wheel  128  rotates, ripping teeth  138  of each plate member  132  strike a portion of trench leading edge  57 , moving upward against leading edge  57  freeing spoil  140  which is then carried within the plate members  132 , arc plate  142 , and the rim structure  130  to the top  141  of the digging wheel  128 . The arc plate  142  keeps the spoil from passing through the rim structure  130  until it reaches the top  141  of the digging wheel  128  where it then falls onto the conveyor assembly  52  for expelling laterally to a spoil bank (not shown) on the side of the excavating machine  30 .  
         [0051]     Each plate member  132  comprises a generally flat plate having at least one ripping tooth  138  mounted thereto, the at least one ripping tooth  138  extending outwardly from rim structure  130 .  
         [0052]      FIG. 10  is a front elevation of rim structure  130  with plate member  132  mounted thereto.  FIG. 11  is a top perspective of an exemplary plate member  132  and  FIG. 12  is a section view taken along line  12 - 12  of  FIG. 11 . Exemplary plate member  132  is shown in  FIGS. 10-12  to include a rectangular steel plate  133 , preferably of steel, having a leading edge  137  which may be, but need not be, tapered from longer outward face  135  to shorter inward face  139 . Plate member  132  is fixed to rim structure  130  which comprises spaced apart parallel rims  129  and  131 . In the exemplary plate member  132  of  FIGS. 10-12 , two ripping teeth  138  are fixed to outward face  135  of plate member  132 . Each ripping tooth  138  comprises a holder  170  and a spike  172 , with holder  170  receiving spike  172  and orienting it at angle a relative to outward face  135 . Angle a is optimally between 32° and 62°, preferably approximately 47° to 52° in the preferred embodiment. It is possible that other inclinations of ripping teeth  138  may be useful depending on the type of rocky condition encountered. Spikes  172  are preferably carbide tips which are driven by wheel assembly  50  against the trench leading edge  57 . Various geometries of spikes  172  are contemplated such as chisels, knives, gouges, scoops and daggers. Variations in the structures of the holders  170  and attachment of spikes  172  thereto may also be made while adhering to the invention.  
         [0053]     Each plate member  132  may further be provided with one or more spades  174  which may be backhoe teeth which extend forward of leading edge  137  of plates  133 . Spades  174  may comprise support legs  178 , which lie along outward face  135  of plates  133 , and shovels  176  which are disposed forward of leading edge  137  of plates  133 . Shovels  176  preferably incline away from outward face  135 .  
         [0054]      FIGS. 13A and 13B  illustrate a series of plate members  132   a - j  carried on rim structure  130 . First plate member  132   a  of series of plate members  132   a - j  comprises a single ripper tooth  138  located generally centrally on outward face  135  of series first plate member  132   a . Also mounted to first plate member  132   a  are a pair of spades  174  spaced on either side of single ripping tooth  138 .  
         [0055]     Spaced from first plate member  132   a  is second plate member  132   b  of series of plate members  132   a - j . Spacing between adjacent plate members may be about six inches while each plate member  132  may be approximately six inches long though variations in both of these dimensions may be selected, preferably within the range of three inches to fifteen inches, it further to be understood that the length of the plate members  132  is not dependent on the spacing between adjacent plate members  132 , nor is the converse required. Second plate member  132   b  comprises a pair of ripping teeth  138  spaced generally equidistantly from the center line  180  of rim structure  130 . Flanking ripping teeth  138  are pairs of spades  174  which may be mounted to outward face  135  of second plate member  132   b  at positions generally equidistant from center line  180 .  
         [0056]     Spaced apart from second plate member  132   b  and mounted to rims  129  and  131  is third plate member  132   c  of series of plate members  132   a - j  which comprises ripping teeth  138  and multiple spades  174 . A centered spade  174  in the form of a backhoe tooth lies on center line  180  with the other spades  174  and the ripping teeth  138  spaced apart generally equidistantly from center line  180 .  
         [0057]     Fourth plate member  132   d  of series of plate members  132   a - j  is spaced similarly from third plate member  132   c  and from the next plate member  132   e  which will follow. Fourth plate member  132   d  comprises a pair of spades  174  flanked by a pair of ripping teeth  138 . It can be observed that ripping teeth  138  on succeeding plate members  132   b - j  form a pattern with ripping tooth  138  of first plate member  132   a  starting on the center line  180  and with ripping teeth  138  moving sequentially outward from the center line  180  with each succeeding plate member  132   b - e . Spades  174  are disposed on each plate member  132  and are placed in locations spaced apart from the ripping teeth  138 . Generally ripping teeth  138  and spades  174  are symmetrically disposed as to center line  180 .  
         [0058]     It is to be understood that the pattern of the ripping teeth  138  and spades  174  on series of plate members  132   a - j  may repeat or the series of plate members  132   a - j  may comprise additional plate members  132 , each of which preferably includes at least one ripping tooth  138  and at least one spade  174 . However, plate members  132  which have neither ripping teeth  138  nor spades  174  may be interspersed within or between series thereof. Furthermore, the use of only one or more ripping teeth  138  on a plate member  132  without spades  174 , or the use of only one or more spades  174  without ripping teeth  138  on a selected plate members is also contemplated.  
         [0059]     Preferably, plate members  132  in series are constructed such that the first of a series of plate members  132  has a single ripping tooth  138  centered thereon while the next plate member  132  in the series includes two ripping teeth  138  each spaced approximately three inches from the centerline  180  of the wheel assembly  50 . The next plate member  132  in the series is provided with two ripping teeth  138  each spaced approximately six inches from the centerline  180  and the subsequent plate member  132  includes two ripping teeth  138  each separated by approximately nine inches from the centerline  180 . Thereafter, the next following plate member  132  includes two ripping teeth each separated from the center line  180  by twelve inches. Then the series may include a next following plate member  132  which includes two ripping teeth  138  straddling the centerline with each ripping tooth  138  at a distance of one and one-half inches from the center line  180 , followed by the next following plate member  132  provided with two ripping teeth  138  each spaced approximately four and one-half inches from the centerline  180 ; followed by a next plate member  132  including two ripping teeth  138  each spaced approximately seven and one-half inches from the centerline  180 ; followed by a next plate member  132  including two ripping teeth  138  each spaced approximately ten and one-half inches from the centerline  180 . Thereafter the next following plate member  132  may be identical to the first plate member  132   a  in the series having a centered single ripping tooth  138  and the series may then repeat as needed to complete the periphery of the rim structure  130 .  
         [0060]     As seen in  FIGS. 13A and 13B , the spades  174  are located on plate members  132  such that they are spaced laterally from the ripping teeth  138  and also symmetrically to the centerline  180 , including in some cases when three spades  174  may be utilized on a plate member  132  with the middle of the spades  174  thereon centered on the centerline  180 . In each case, the spades  174  are directed toward the direction of movement of the plate members  132  as the wheel assembly  50  is turned while the ripping teeth  138  are each angularly directed outward from the plate members  132  with the spikes  172  thereof directed toward the direction of rotational movement of the rim structure  130 . Spades  174  extend forward of leading edges  137  of plate member  132  while spikes  172  are preferably located near the trailing edges  133  of plate members  132 .  
         [0061]     The ripping tooth  138  of first plate member  132   a  shatters the trench leading edge  57  of the rocky ground  58  while the ripping teeth  138  of each succeeding plate member  132  strike a different area and may clear the spoil  140  created by the ripping tooth  138  of the preceding plate members  132  or the ripping teeth  138  of the following plate members  132  may shatter a different area of the trench leading edge  57 .  
         [0062]     The shovels  176  of each spade  174  do not extend outward from plate  133  as far as the ripping teeth  138  do but do serve to scoop rock pieces and rocky soil in the trench, feeding the spoil  140  toward the arc plate  142  and upward such that spoil  140  will pass to the top  141  of wheel assembly  50  and be deflected by deflective face  150  ( FIG. 14 ) onto the conveyor assembly  52 . In addition, shovels  176  serve to excavate non-rocky soil which may be encountered, thereby permitting the invention machine to be used on both rocky and non-rocky soils.  
         [0063]     Deflecting member  144  is operably attached to the wheel frame assembly  44  at  146 . The deflecting member  144  is shown in detail in  FIG. 14  and is positioned within an interior profile  148  defined by of the rim structure  130  and the plate members  132  of the digging wheel  128  in  FIG. 15 . The deflecting member  144  is positioned at an angle with a deflecting face  150  located at the top  141  of the digging wheel  128  in such a manner that it removes the spoil  140  which has accumulated in the rim structure  130  between the plate members  132  of the digging wheel  128  and the arc plate  142 . Deflecting member  144  directs the spoil  140  downwardly onto the conveyor assembly  52 . The deflecting face  150  corresponds substantially in size and shape to the interior profile  148  of the rim structure  130  and the plate members  132 , the deflecting face  150  thereby fitting within the interior profile  148  formed by the rim structure  130  and the plate members  132  to remove substantially all of the spoil  140  which has accumulated within interior profile  148 .  
         [0064]     The deflecting face  150  may be arcuate in lateral cross-section ( FIG. 14 ) and in longitudinal cross-section resulting in a concave shape in order to deflect the spoil  140  downward.  
         [0065]     In the preferred embodiment, the deflecting face  150  is rigidly attached to a support member  152  which is carried on the frame assembly  144 . Compression coil springs (not shown) within housing  154  may longitudinally bias the deflecting face  150  into position within the interior profile  148  of the rim structure  130  and the plate member  132  as well as permit the deflecting face  150  to retract upon contact with an obstruction (not shown) within the interior profile  148  of the rim structure  130  and the plate member  132 . This configuration allows for positive cleaning while preventing damage upon contact with an obstruction.  
         [0066]     An alternative embodiment of the cleaning member  144  is shown in  FIG. 16 . In this embodiment, a cleaning face  170  is attached directly to a mounting arm  172  which is pivotally mounted to a wheel frame assembly  174  about a horizontal axis  176 . A coiled spring  178  is rigidly connected between the mounting arm  172  at  180  and the wheel frame assembly  174  at  182  to provide alternative biasing and retraction means. However, the cleaning face  184  and the ultimate position of the cleaning face  184  within the interior profile  148  of the rim structure  130  and the bucket member  132  would be identical.  
         [0067]     In the preferred embodiment, it is found that the wheel speed may be accelerated over that which is known in the art and that the cutting effect of the earth cutting assembly  40  may be improved by rotation of the wheel assembly  50  at a sufficient speed that the speed of travel of any of ripping teeth  138  across the leading trench edge  57  is not less than approximately fifteen feet per second, and preferably approximately at least eighteen feet per second. The inclusion of the deflecting member  144  and the conveyor assembly  52  in coordination with the novel plate members  132  mounted on the rim structure  130  enables the rapid rotation of the wheel assembly  52  such that the ripping teeth  138  pass the leading trench face  57  at an angular velocity of in excess of fifteen feet per second. In some ground conditions however, it may be necessary to operate the wheel assembly  50  at a slower speed at which the excavating machine will remain fully functional.  
         [0068]     The conveyor assembly of the present invention is shown in  FIGS. 17-20 . The conveyor assembly  52  is operably attached to the wheel frame assembly  44  in a suspended manner at  186  and  188 . This allows the conveyor assembly to be tilted from one side to another depending upon from which side the spoil  140  is to be expelled. The conveyor assembly  52  comprises an interior portion  190  bounded by a first end roller  192  and a second end roller  194  opposite to the first end roller  192 , an endless conveyor belt  196  about the first end roller  192  and the second end roller  194 , a first side assembly  198  and a second side assembly  200  opposite to the first side assembly  198 , all to prevent the spoil  140  from entering the interior portion  190  of the conveyor assembly  52 .  
         [0069]     The conveyor assembly  52  further comprises a top plate  202  on which the endless conveyor belt  196  slides. In the preferred embodiment, this top plate  202  is made of an ultra-high molecular weight plastic to provide a minimal amount of friction between the endless conveyor belt  196  and the top plate  202 . However, it is anticipated that other materials could be used. While the top plate  202  is shown in the preferred embodiment as separate plates  204  and  206  which are located side-by-side with a longitudinal channel  208  therebetween, it is to be understood that a single top plate could also be used having a longitudinal groove therein (not shown). The top plates  204  and  206  of the conveyor assembly  52  extend laterally beyond the first side assembly  198  and the second side assembly  200 , respectively, in a manner so as to overlap the side assemblies  198  and  200  to prevent spoil  140  from entering the interior portion  190  of the conveyor assembly  52 .  
         [0070]     In the preferred embodiment, the endless conveyor belt  196  includes a series of finger-like projections  210  ( FIGS. 19 and 20 ) along its underside  212  corresponding in alignment with the longitudinal channel  208  between the first top plate  204  and the second top plate  206  of the conveyor assembly  52  in order to act in combination as a guide for centering the endless conveyor belt  196  on the conveyor assembly  52 . In addition, the first end roller  192  and the second end roller  194  each include an annular groove  214  and  216 , respectively, in alignment with the longitudinal channel  208  between the first top plate  204  and the second top plate  206  of the conveyor assembly  52  in order to receive the finger-like projections  210  on the underside  212  of the endless conveyor belt  196  again to center the endless conveyor belt  196  on the conveyor assembly  52 . The centering of the endless conveyor belt  196  on the conveyor assembly  52  is also assisted by a tapering of the first end roller  192  and the second end roller  194  wherein the center portion  218  and  220  of the first end roller and second end roller, respectively, is larger in diameter than the end portions  222  and  224  and  226  and  228  of the first end roller  192  and the second end roller  194 , respectively.  
         [0071]     A belt tension adjuster  230  allows an end member  232  of the first side assembly  198  and an end member  234  of the second side assembly  200 , respectively, to be extended or retracted as necessary The tension adjuster  230  comprises a thumb screw  231  which, upon turning along threaded rod  236 , either extends or retracts the end members  232  and  234  of the first side assembly  198  and the second side assembly  200 , respectively, along with the second end roller  194 . The first end roller  192  is rigidly connected along with end members  238  and  240  of the first side assembly  198  and the second side assembly  200 , respectively.  
         [0072]     The first side assembly  198  and the second side assembly  200  further includes downwardly extended flanges  242  and  244 , respectively, for preventing the spoil  140  from entering the interior portion  190  on the underside  246  of the conveyor assembly  52 . For the minimal amount of spoil  140  that does enter the interior portion  190  of the conveyor assembly  52 , a plow assembly is operably attached therein to direct the spoil  140  back out from the interior portion  190  of the conveyor assembly  52 . The shoe assembly  54  is a diamond-shaped configuration of stop plates  250 ,  252 ,  254  and  256  which are angled towards the first side assembly  198  and the second side assembly  200 . Accordingly, as spoil riding on the underside  212  of the endless conveyor belt  196  comes into contact with the stop plates  250 - 256  it is directed out of the conveyor assembly  52 .  
         [0073]     Once again, while the conveyor assembly  52  of the present invention is shown on an excavating machine  30  having a rock wheel trencher assembly  42 , the conveyor assembly  52  could be incorporated with any type of excavating machine having earth cutting means either as original equipment or sold separately as a retrofit part for existing equipment.  
         [0074]     The shoe assembly  54  of the present invention is shown in  FIGS. 21-26 . The shoe assembly  54  includes a post member  258  for operable attachment at  260  with the supporting frame assembly  44 . The shoe assembly further includes side plates  262  and  264  for contact with the side walls of the trench  56  in order to prevent a cave-in of the side walls of the trench  56  during use. The side plates  262  and  264  are supported and maintained in a spaced relationship by a tubular support assembly  266  which extends downwardly from the post member  258 .  
         [0075]     Grooving means  268  are operably attached along the bottom edge  270  of the shoe assembly  54  and extend therebelow to form a groove  272  in the bottom  274  of the trench  56 . In the preferred embodiment, the grooving means  268  comprise adjustable groove means  276  for adjusting the radial dimension of the groove  272 . The adjustable groove means  276  includes a mounting assembly  278  including a mounting plate  280  rigidly connected to a bottom member  282  of the shoe assembly  54 . The mounting assembly  278  of the adjustable groove means  276  also includes side mounting plates  284  and  286  rigidly connected to sidewalls  262  and  264 , respectively, of the shoe assembly  54  and a rear mounting plate  288  operably attached between the side mounting plates  284  and  286 .  
         [0076]     Suspended within the mounting assembly  278  and pivotally connected about a pivot member  290  extended rearwardly from the front mounting plate  280  is the adjustable groover assembly  291  of the adjustable groove means  276 . The adjustable groover assembly  291  comprises a first arcuate groove plate  292  and a second arcuate groove plate  294  having apertures  296  and  298 , respectively, for receiving the pivot member  290  extended rearwardly from the front mounting plate  280 , the first arcuate groove plate  292  and the second arcuate groove plate  294  in combination resulting in an arc  300  of varying radius for forming the groove  272  in the bottom  274  of the trench  56 .  
         [0077]     Means for pivoting the first arcuate groove plate  292  relative to the second arcuate groove plate  294  are included comprising a linear actuator  302  having a first end  304  and a second end  306  opposite to the first end  304 .  
         [0078]     The first end  304  of the linear actuator  32  is operably attached to a hand-crank assembly  308  which is operably attached at the top edge  310  of the shoe assembly  54 . The second end  306  of the linear actuator  302  is operably attached to a yoke member  312  having an aperture  314  for receiving a pivot member  316  therein. First and second link members  318  and  320  each having a first end  322  and  324 , respectively, and a second end  326  and  328 , respectively, are pivotally attached at their first ends  322 ,  324  to the yoke member  312  and at their second ends  324 ,  326  to the first arcuate groove plate  292  and the second arcuate groove plate  294 , respectively, at pivot points  328  and  330 , respectively.  
         [0079]     Accordingly, as the linear actuator  302  is extended, the link members  318  and  320  extend the first arcuate groove plate  292  and the second arcuate groove plate  294  apart to form a groove of a larger radius. Likewise, when the linear actuator  302  is retracted, the link members  318  and  320  retract the first arcuate groove plate  292  relative to the second arcuate groove plate  294  to create a groove of a smaller radius.  
         [0080]     A nose cone member  332  extends in front of the front mounting plate  280  in the direction of travel of the excavating machine  30  to penetrate the ground  58  to make way for the adjustable groover assembly  291 .  
         [0081]     And again, while the adjustable groover assembly  276  of the present invention is shown on an excavating machine  30  having a rock wheel trencher assembly  42 , it is to be understood that the adjustable groover assembly  276  could be incorporated with any type of excavating machine having earth cutting means as original equipment or sold separately as a retrofit part for existing equipment.  
         [0082]     The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited as those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention.