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BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to excavators and more particularly to a self-propelled rotary excavating machine that cuts new drainage ditches and maintains existing drainage ditches with laser precision. 
     2. Discussion of the Background 
     Alluvial soils located on flood plains of streams need to be drained before they can be developed, for example, for agricultural uses. 
     The parcels of land to be drained are fitted into a general drainage plan for the entire acreage. Typically, the excavation of a drainage ditch was accomplished with draglines and dozers. The draglines were, typically, of various sizes, depending on the required excavation and the distance necessary to reach the excavation area. A further factor to consider was to place the excavated soil, known as spoil, in the vicinity of road or levee construction. Large drainage ditches required the use of a large dragline having a long boom. Smaller field and lateral ditches which feed into the larger drainage ditches were excavated by smaller draglines. 
     The use of the draglines either to form the drainage ditch or to dredge a preexisting drainage ditch requires the additional use of dozers to move and shape the resulting spoil into roads or levees or to spread it out in the adjoining fields as drainage ditches were being excavated. 
     During the early 1970&#39;s, trackhoes became available to cut drainage ditches. Trackhoes are more efficient for excavating small ditches than are draglines. At that time, trackhoes were used for field drainage and other development that did not require the use of a large capacity machine. Trackhoes and draglines equipped with wide tracks can operate under very wet field conditions. However, a problem with using trackhoes and draglines in wet conditions is that leveling wet spoil will result in future crop losses in the affected area. 
     Also used to cut drainage ditches were rotary power ditchers. A rotary power ditcher is a device mounted on a tractor&#39;s 3-point hitch driven by the power take-off shaft. The use of this device was usually for making a network of small water furrows cut in small natural drains and through field depressions connecting to the field ditches. In some instances, the small water furrows would extend up to a quarter of a mile in length. Attempting to move water run-off up to a quarter mile on nearly level or flat land via a small water furrow usually created several problems. Such problems occur during heavy rainfall when large volumes of water accumulate and flow across the field, thus, scouring the field in some areas. Water moving across a freshly cultivated field under these conditions will move silt into the field ditches. Some of the furrows will then be closed by silt, thus, resulting in water ponding in field depressions. The soil surrounding the ponded area then becomes saturated with water. The silt also forms silt bars in field ditches which reduce their drainage efficiency. 
     Drainage ditches which are filled with silt must be re-excavated so as to maintain efficient drainage of the field. Thus, there is a maintenance schedule for the regular clearing of the silt-filled drainage ditches. The annual ongoing and recurring high cost of ditch maintenance performed by slow moving hydraulic trackhoes and dozers was unacceptable. 
     Hydraulic trackhoes are more efficient than draglines in excavating and maintaining field and lateral ditches. However, the efficiency of hydraulic trackhoes is not comparable to the speed and efficiency of smaller tractor mounted rotary powered ditchers. The small tractor mounted rotary powered ditchers are suitable for cutting small water furrows to carry water run-off from field depressions to field drainage ditches. 
     Thus, there is a need for an efficient device for excavating water furrows which cuts a water furrow such that it does not fill-up with silt as quickly as do water furrows cut by preexisting devices. 
     SUMMARY OF THE INVENTION 
     The invention meets the aforementioned need to a great extent by providing a self-propelled rotary excavator that excavates a field drainage ditch in such a manner that it can be done swiftly, efficiently, economically, and which can reduce the need for periodic maintenance of the drainage ditch. 
     In one embodiment of the invention, the self-propelled rotary excavator includes a mobile platform, a lateral telescoping boom attached on one end to the mobile platform, and on the other end to a vertical telescoping boom to which is attached a rotary cutting device that includes an adjustable shield for directing the discharge of spoil. 
     In still another aspect of the invention, the self-propelled rotary excavator includes a laser control system to control the horizontal and vertical positions of the rotary cutter. 
     In another preferred embodiment of the invention, the self-propelled rotary excavator includes a vehicular chassis mounted on four wheels, each wheel having its own independent source of power. 
     The present invention provides a precision self-propelled rotary excavator with a cutting device capable of cutting deeply into the soil to make a deep drainage ditch in a rough terrain environment. The prior art does not disclose the use of a self-propelled rotary excavator that can operate over rough terrain with precise lateral and vertical rotor positioning while evenly distributing the spoil on the field. Furthermore, the self-propelled rotary excavator is able to operate where draglines and trackhoes cannot, and furthermore it can operate the larger, heavy rotary cutting device which is not possible with a tractor. 
     Another aspect of the invention is that it will evenly distribute wet spoil such that crop losses are avoided. 
     Still another aspect of the invention is the provision of the ability to clean and maintain an existing ditch without having to straddle the ditch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description and accompanying drawings, wherein: 
     FIG. 1 is a front view of an excavator according to a preferred embodiment of the invention. 
     FIG. 2 is a partial perspective view of the excavator of FIG.  1 . 
     FIG. 3 is a partial front view of the excavator of FIG. 1 showing the lateral and vertical booms and the rotary cutting head rotor. 
     FIG. 4 is a front view of the rotary cutting head rotor. 
     FIG. 5 is a front view of the rotary cutting head rotor showing the adjustable extension shield in the extended position and the rotary cutting head adjustable deflector shield in a deflected position. 
     FIG. 6 is a partial sectional view of the lateral telescopic extendable boom and the lateral telescopic stationary boom. 
     FIG. 7 is a partial view of the lateral boom base mounting assembly. 
     FIG. 8 is a perspective view of an embodiment of the invention from a different angle as compared to FIG.  1 . 
     FIG. 9 is a perspective view of the rotary cutting head rotor. 
     FIG. 10 is a perspective view from the rear of an embodiment of the invention. 
     FIG. 11 is a side view of the lateral boom deck extension. 
     FIG. 12 is a view of the axle attachment to the chassis. 
     FIG. 13 is a perspective view of the rotary cutting head and wheel drive pumps layout. 
     FIG. 14 is a side view of the rotary cutting head and wheel drive pumps layout. 
     FIG. 15 is a perspective view of the rotary cutting head and wheel drive pumps layout displaying connection of the hydraulic tubing. 
     FIG. 16 is a view of the steps and safety handrail. 
     FIG. 17 is a front view of the rotary cutting head rotor hub. 
     FIG. 18 is perspective view of the rotary cutting head rotor and displaying the rotary cutting head position adjustment turnbuckle and rotary cutting head hydraulic motor and gear box. 
     FIG. 19 is a view of the interior of the cab. 
     FIG. 20 is a view of the sectional valve bank. 
     FIG. 21 is a view of the excavator controls inside the cab. 
     FIG. 22 is a view of the excavator controls. 
     FIG. 23 is a view of the laser controls. 
     FIG. 24 is a view of the device cutting a ditch. 
     FIG. 25 is a front view showing an adjustment of the laser receiver. 
     FIG. 26 is a view of the self-propelled rotary excavator cutting a ditch with the device which emanates the laser beam on a tripod in the background. 
     FIG. 27 is a partial front view of the excavator of FIG.  1 . 
     FIGS. 28 a-c  are partial front views of the excavator of FIG. 1 showing the rotary cutting head assembly and hydraulic hose support in different positions. 
     FIGS. 29 a-b  are front views of the rotary cutting head assembly with an adjustable extension shield and an adjustable deflection shield in various positions. 
     FIG. 30 shows front and side view of the rotary cutting head assembly. 
     FIG. 31 shows a partially exposed rotary cutting head assembly and various views of the rotary cutting head in a clockwise configuration. 
     FIG. 32 shows a partially exposed rotary cutting head assembly and various views of the rotary cutting head in a counter-clockwise configuration. 
     FIGS. 33 a-c  are partial perspective views of the rotary excavator of FIG. 1 showing a front axle. 
     FIG. 34 is a top view of a front axle assembly. 
     FIG. 35 is a top view of a rear axle assembly. 
     FIG. 36 is a partial rear view of the excavator of FIG. 1 showing a rear axle mounted to a frame. 
     FIG. 37 is a perspective view of the frame of the excavator of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the figures, wherein like reference numerals designate identical or corresponding parts throughout the several views, FIG. 1 is a front view of one embodiment of a self-propelled rotary excavator according to the present invention. Attached to the frame  100  is a left front fender  106 , and a right front fender (not shown in FIG.  1 ). Also attached to the frame  100  is a water reservoir tank (not shown in FIG.  1 ), a hydraulic fluid reservoir (not shown in FIG.  1 ), a front vehicle frame beam  104 , a cab  20 , a boom guide  40 , and a lateral telescopic boom assembly  200 . Attached to the distal end of the lateral telescopic boom assembly  200  is the vertical boom assembly  300 . Attached to the top end of the vertical boom assembly  300  is a laser assembly  500  including a laser alignment control receiver  502  and a vertical sensing depth control laser receiver  508 . Further shown in FIG. 1 is the right front lateral boom vertical guide  42  and the left front lateral boom vertical guide  44  of the boom guide  40 . 
     The lateral telescopic boom assembly  200  includes a pair of lateral boom positioning hydraulic cylinders  216  and  218  ( 216  shown in FIG. 1) attached to the lateral boom base mounting assembly  236  and another end of the lateral boom hydraulic cylinder  216  is connected to the lateral telescopic stationary boom  204  to a mount  220 . A lateral telescopic extendable boom  202  is movably attached within the lateral telescopic stationary boom  204 . A lateral telescopic extendable boom hydraulic cylinder  206  is attached to the lateral telescopic stationary boom  204  at mount  208 . A lateral telescopic extendable boom hydraulic cylinder ram  210  is movably attached to the lateral telescopic extendable boom hydraulic cylinder  206 . The other end of the lateral telescopic extendable boom hydraulic cylinder ram  210  is attached to the lateral telescopic extendable boom  202 . 
     Pivotally attached at mount  310  to the lateral telescopic extendable boom  202  is a vertical telescopic stationary boom  304 . Movably mounted within the vertical telescopic stationary boom  304  is a vertical telescopic extendable boom  302 . A vertical telescopic boom position control cylinder  312  is pivotally attached at one end to the lateral telescopic extendable boom  202  (at mount  212 ) and at the other end to the vertical telescopic stationary boom  304  (at mount  314 ) so as to pivot the vertical boom assembly  300  relative to the lateral telescopic boom assembly  200 . 
     Attached to one end of the vertical telescopic extendable boom  302  of the vertical boom assembly  300  is the rotary cutting head assembly  400 . The rotary cutting head assembly  400  includes a rotary cutting head shield  402  and a rotary cutting head rotor  414 . Attached to atop end of the vertical telescopic extendable boom  302  is a laser alignment control receiver  502 . Also connected to the vertical telescopic extendable boom  302  is the vertical sensing depth control laser receiver  508 . 
     FIG. 2 is a partial perspective view of the invention as shown in FIG.  1 . FIG. 2 displays the right front fender  102  and the right rear fender  108  attached to the frame  100  (FIG.  1 ). Also connected to the frame  100  is the right front wheel hub  114  and the right rear wheel hub  122 . A right front wheel  112  is attached to the right front wheel hub  114  and a right rear wheel  120  is attached to the right rear wheel hub  122 . Further shown in FIG. 2 is a rear-central frame section  130  attached to the frame  100  and the cab  20  attached to the frame  100 . The cab  20  includes a cab screen protector  22 . Further attached to the frame  100  is a safety hand rail  26 , grated steps  25  and a frontal cab supporting base  24 . The frame  100  further includes a front-central frame section  128 . 
     Also shown in FIG. 2 is the right front lateral boom vertical guide  42 , the left front lateral boom vertical guide  44 , the right rear lateral boom vertical guide  46 , and the left rear lateral boom vertical guide  48  of the boom guide  40  (FIG. 1) attached to the frame  100 . Attached to the lateral telescopic stationary boom  204  is a lateral boom rest vertical guide  52  and a lateral boom rest  50 . The lateral boom rest vertical guide  52  is also slidably mounted in the boom guide  40  between the right front lateral boom vertical guide  42  and the left front lateral boom vertical guide  44 . A portion of the lateral boom rest vertical guide  52  is also slidably mounted between the right rear lateral boom vertical guide  46  and the left rear lateral boom vertical guide  48 . 
     One end of each of the forward twin lateral boom hydraulic cylinder  216  and the rear twin lateral boom hydraulic cylinder  218  are rotatably mounted to the lateral boom base mounting assembly  236 . The other end of each of the cylinders  216 ,  218  are rotatably connected to lateral boom hydraulic cylinder ram pins. Cylinder  216  is shown connected to the forward ram pin  220 . Cylinders  216  and  218  are connected to each side of the lateral telescopic stationary boom  204  of the lateral telescopic boom assembly  200 . 
     Referring now to FIG. 27, the elevation of the lateral boom assembly  200  is controlled by a four-stage hydraulic cylinder  222 . The forward and rear twin boom hydraulic cylinders  216 ,  218 , are disengaged during operation of the machine  10 . This allows the lateral telescopic boom assembly  200  free upward movement in the event an obstacle is encountered during excavation. The main purpose of the twin lateral boom hydraulic cylinders  216 ,  218  is to elevate the lateral telescopic boom assembly  200  when the lateral boom deck extension hydraulic cylinder  238  is being used to reposition the lateral boom base mounting assembly  236  as described in further detail in connection with FIG.  7 . 
     Referring now back to FIG. 2, the lateral telescopic extendable boom  202  is slidably mounted within the lateral telescopic stationary boom  204 . A lateral telescopic stationary boom roller  232  is rotatably mounted near an end of the lateral telescopic stationary boom  204 . The lateral telescopic extendable boom  202  is in rolling contact with the lateral telescopic stationary boom roller  232 . 
     The lateral telescopic extendable boom hydraulic cylinder ram  210  of the lateral telescopic extendable boom hydraulic cylinder  206  is rotatably connected to the lateral telescopic extendable boom hydraulic cylinder ram pin  208 . The lateral telescopic extendable boom hydraulic cylinder ram pin  208  is attached to a lateral telescopic extendable boom hydraulic cylinder ram pin mounting bracket  212 . In tun, the lateral telescopic extendable boom hydraulic cylinder ram pin mounting bracket  212  is connected to the lateral telescopic extendable boom  202 . 
     A hydraulic hose support  214 , which is depicted further in FIGS. 28 a-c , is provided to keep hydraulic hoses  215  from being damaged during movement of the lateral telescopic extendable boom  202 . The hose support  214  includes two legs  214   a ,  214   b . The proximal ends of the legs are pivotally connected. The distal end of leg  214   a  is rotatably mounted on mounting bracket  230  on the lateral telescopic stationary boom  204 . The distal end of leg  214   b  is rotatably mounted on mounting bracket  228  on the lateral telescopic extendable boom  202 . As shown in FIGS. 28 a-c , this arrangement allows the hose support  214  to extend and retract along with the lateral telescopic boom  202  while keeping the hoses  215  safe. Further shown in FIG. 2 are the quick release hydraulic hose connectors  316 . 
     Attached to an end of the lateral telescopic extendable boom  202  is the vertical telescopic stationary boom  304 . The vertical telescopic extendable boom  302  (shown in FIG. 3) is slidably mounted in the vertical telescopic stationary boom  304 . A vertical boom lifting bracket  318  is provided on the vertical telescopic stationary boom  304 . 
     FIG. 3 is a partial front view of the invention showing the lateral telescopic boom assembly  200 , the vertical boom assembly  300  and the rotary cutting head assembly  400 . FIG. 3 further shows the right front fender  102  attached to the frame  100  and the front vehicle frame beam  104  of the frame  100 . Also shown is the right high pressure water coupling receptacle  160 . The cab  20  is shown along with the cab screen protector  22 . The right and left front lateral boom vertical guides  42 ,  44  and the right and left rear lateral boom vertical guides  46 ,  48  of the boom guide  40 , which attach to the frame  100 , are also shown. 
     FIG. 3 further shows a pivot pin mounting bracket  314  attached to the vertical telescopic stationary boom  304 . One end of the vertical telescopic boom position control cylinder  312  is rotatably connected to the mounting bracket  314 . The other end of the vertical telescopic boom position control cylinder  312  is connected to the mounting bracket  212  on the lateral telescopic extendable boom  202 . The vertical telescopic boom position control cylinder  312  controls the angular position of the vertical telescopic stationary boom  304  relative to the lateral telescopic extendable boom  202 . 
     The rotary cutting head assembly  400  is shown connected to the vertical telescopic extendable boom  302 . The rotary cutting head assembly  400  includes a rotor  414 . Attached to the rotor  414  are eight rotary cutting head blade mounting brackets  420 . Attached to the rotary cutting head blade mounting brackets  420  are rotor blades  418  and rotor impeller blades  416 . As shown in FIGS. 31 and 32, the brackets may be equipped with blades  416 ,  418  arranged for either clockwise or counter-clockwise rotation, and the blades  416 ,  418  may be arranged in various configurations. In the center of the rotor  414  is attached a rotary cutting head central reversible blade  422 . 
     Surrounding a part of the rotor  414  are a rotary cutting head shield  402  and a rotary cutting head frontal extension shield  404 . The extension shield  404  is attached to the head shield  402 , which are also shown in FIG.  30 . The rotary cutting head shield  402  partially encloses the rotor  414 . In operation, the rotary cutting head shield  402  contains the spoil material as it is excavated from the soil surface and set in motion. The rotary cutting head shield  402  then directs the trajectory of the spoil to a controlled point of departure through a shield outlet  409 . A deflector shield  424  should be installed within the shield outlet  409  when the rotor  414  is moving in a counter-clockwise direction. The deflector shield  424  prevents the spoil material from recycling around the rotor  414  and accumulating in the shield  402  by deflecting material away from the rotor  414 . 
     The rotary cutting head frontal extension shield  404  is a forward extension of the rotary cutting head shield  402 . The frontal extension shield  404  prevents excavated material from moving forward and directs it back toward the rotor  414  so it will be expelled through shield outlet  409 . 
     Referring now to FIGS. 29 a  and  29   b , rotatably connected to the rotary cutting head shield  402  are a rotary cutting head adjustable extension shield  406  and a rotary cutting head adjustable deflector shield  408 . The adjustable extension shield  406  may be extended in varying amounts as shown in FIGS. 29 a  and  29   b . The adjustable extension shield  406  is extended when making excavations less than one half of the diameter of the rotor  414 . This prevents excavated material from moving toward the excavator  10  and the laser equipment  500 . The adjustable extension shield  406  is used when the rotor  414  is excavating with either a clockwise or counter-clockwise rotation. 
     An adjustable extension shield cylinder  412  actuates position of the adjustable extension shield  406 . The ram end of the cylinder  412  is connected to the adjustable extension shield  406  and the cylinder end is connected to a mounting bracket on the rotary cutting head shield  402 . 
     The rotary cutting head adjustable deflector shield  408  controls the trajectory of spoil material as it exits the shield outlet  409 , and it protects the laser assembly  500  from flying objects. The position of the deflector shield  408  is controlled by a deflector shield hydraulic cylinder  410 . The ram end of the cylinder  410  is connected to the deflector shield  408  and the cylinder end is connected to the cutting head shield  402 . 
     Referring now back to FIG. 3, the vertical telescopic stationary boom  304  rotates with respect to the lateral telescopic extendable boom  202  about the vertical telescopic boom pivot pin  310 . A vertical telescopic boom pendulous sensing device  306  is attached to the vertical telescopic stationary boom  304 . FIG. 3 further shows the attachment of the laser equipment  500 . A laser alignment control receiver mounting bracket  504  is attached to the vertical telescopic extendable boom  302 . Attached to the laser alignment control receiver mounting bracket  504  is a laser alignment control receiver position adjustment tube  506 . Slidably attached to the laser alignment control receiver position adjustment tube  506  is the laser alignment control receiver  502 . Also attached to the vertical telescopic extendable boom  302  is a vertical sensing depth control laser receiver mount  510 . Slidably connected to the laser receiver mount  510  is the vertical sensing depth control laser receiver  508 . 
     FIG. 4 is a front view of the rotary cutting head assembly  400 . Also shown is the rotary cutting head adjustable extension shield cylinder  412  which is rotatably connected at one end to a mounting bracket attached to the rotary cutting head shield  402  and which is rotatably connected at its other end to the rotary cutting head adjustable extension shield  406 . Also shown is the rotary cutting head adjustable deflector shield hydraulic cylinder  410  which is rotatably connected at one end to a mounting bracket attached to the rotary cutting head shield  402  and is rotatably connected at its other end to the rotary cutting head adjustable deflector shield  408 . FIG. 4 further displays the vertical telescopic boom pivot arm  308  and the vertical telescopic boom pivot pin  310 . The vertical telescopic boom pivot arm  308  is attached to the lateral telescopic extendable boom  202 . The vertical telescopic stationary boom  304  is rotatably connected to the vertical telescopic boom pivot pin  310  via the vertical telescopic boom pivot arm  308 . 
     FIG. 5 is a front view of the rotary cutting head rotor  414  showing the rotary cutting head adjustable extension shield  406  in the extended position and the rotary cutting head adjustable deflector shield  408  in a deflected position. 
     FIG. 6 is a partial sectional view of the lateral telescopic extendable boom  202  and the lateral telescopic stationary boom  204 . FIG. 6 shows the interaction of a lateral telescopic extendable boom internal roller  234  rotatably connected to the lateral telescopic extendable boom  202 . The lateral telescopic extendable boom internal roller  234  is in rolling contact with an interior surface of the lateral telescopic stationary boom  204 . Likewise the lateral telescopic stationary boom roller  232  which is rotatably mounted on the lateral telescopic stationary boom  204  is in rolling contact with an outer surface of the lateral telescopic extendable boom  202 . 
     FIG. 7 is a partial view of the lateral boom base mounting assembly  236 . The lateral telescopic stationary boom  204  is rotatably connected to the lateral boom base mounting assembly  236 . The lateral boom base mounting assembly  236  is in turn slidably mounted on the frame  100 . A lateral boom deck extension hydraulic cylinder  238  is connected at one end to the frame  100  and at its other end to the lateral boom base mounting assembly  236 . Both the forward and rear twin lateral boom hydraulic cylinders  216  (cylinder  216  is not visible in FIG. 7 because it is obscured by the identical cylinder  218 —cylinder  216  is partially visible in FIG.  11 ),  218  are rotatably connected at one of each of their ends to the lateral boom base mounting assembly  236  and the remaining end of each are rotatably connected to the lateral telescopic stationary boom  204 . A four-stage lateral boom hydraulic cylinder  222  is rotatably connected to the frame  100 . The other end of the four stage lateral boom hydraulic cylinder  222  is rotatably connected to a lateral boom rest  50 . The lateral boom rest  50  contacts the lateral telescopic stationary boom  204 . 
     FIG. 8 is a perspective view of an embodiment of the invention from a different angle as compared to FIG.  1 . FIG. 8 provides a partial rear view of the rotary cutting head assembly  400 . The rotary cutting head rotor  414  is shown with rotary cutting head rotor impeller blades  416  and rotary cutting head rotor blades  418  attached to the rotary cutting head blade mounting brackets  420 . Also shown is the rotary cutting head hydraulic drive motor  426 . 
     The laser receiver mount  510  attaches to the vertical boom assembly  300  through a telescoping laser depth control receiver mounting base  512 . 
     A vertical telescopic boom hydraulic cylinder  320  is attached to the vertical telescopic stationary boom  304 . Slidably mounted in the vertical telescopic boom hydraulic cylinder  320  is a vertical telescopic boom hydraulic cylinder ram  322 . An end of the vertical telescopic boom hydraulic cylinder ram  322  is pivotally connected to a vertical telescopic boom hydraulic cylinder ram pin  324  which is connected to the rotary cutting head assembly  400 . 
     The angular position of the rotary cutting head assembly  400  is adjustable via a rotary cutting head position adjustment turnbuckle  432 . The rotary cutting head position adjustment turnbuckle  432  is pivotally connected at each of its ends, one end connected to the rotary cutting head assembly  400  and the other end connected to the vertical telescopic extendable boom  302 . The vertical telescopic boom hydraulic cylinder  320  is fitted with vertical telescopic boom hydraulic cylinder quick release hydraulic hose connectors  332 . Additionally, the rotary cutting head assembly  400  is equipped with rotary cutting head hydraulic hose quick coupler connectors  446 . 
     FIG. 9 is a perspective view of the rotary cutting head assembly  400 . The rotary cutting head shield housing  430  is shown. Attached to the rotary cutting head shield housing  430  is a rotary cutting head mounting plate  428 . Attached to the rotary cutting head mounting plate  428  is a gearbox and the rotary cutting head hydraulic drive motor  426 . 
     FIG. 10 is a perspective view from the rear of an embodiment of the self-propelled rotary excavator  10  of FIG.  1 . Shown is the rear vehicle frame beam  132  of the frame  100 . Also shown are the left rear fender  110  attached to the frame  100 . The diesel engine  90  and expanded steel muffler safety shields  92  and diesel fuel tank  94  are also mounted on the frame  100 . Further illustrated are the left front wheel  116  and the left rear wheel  124  along with the left front fender  106 . On the left side of the self-propelled rotary excavator is a left high pressure water coupling receptacle  162  and priority flow regulator valves  64 . On the right hand side of the self-propelled rotary excavator  10  sets the cab  20  mounted on the frame  100 . The cab  20  includes a cab door  32  and an upper hinged rear window  30 . Also shown are the deck grating  134  and right rear fender  108  both mounted on the frame  100 . 
     FIG. 11 is a side view of FIG.  7 . FIG. 11 shows the lateral boom deck extension sliding base plate  246  slidably mounted on the frame  100 . The lateral boom deck extension sliding base plate  246  is constrained by the lateral boom deck extension guide  244  which is fixedly attached to the frame  100 . Mounted on the lateral boom deck extension sliding base plate  246  is a lateral boom deck extension hydraulic cylinder mounting bracket  240 . Mounted on the lateral boom deck extension hydraulic cylinder mounting bracket  240  is a lateral boom deck extension hydraulic cylinder ram pin  242 . Rotatably connected to the lateral boom deck extension hydraulic cylinder ram pin  242  is a lateral boom deck extension hydraulic cylinder  238 . The other end of the lateral boom deck extension hydraulic cylinder  238  is connected to the frame  100 . A perspective view of the lateral boom base mounting assembly  236  can be seen with reference to FIG.  37 . 
     FIG. 12 is a perspective view of the attachment of the front axle  136  to the frame  100  as viewed from just below the front vehicle frame beam  104  of FIG.  1 . Shown is a front axle frame section  138  of the frame  100 . A triangular plate  144  is welded to both the front and rear of the axle  136 . The triangular plate  144  is pivotally mounted to the frame section  138  by a front axle hinge pin  146 . A left-front vertical axle guide  142  constrains the fore and aft movement of the front axle  136 , while allowing the front axle  136  to rotate about front axle hinge pin  146 . As can be seen with reference to FIGS. 33 a ,  33   b  and  33   c , this arrangement allows the axle  136  to pivot on uneven terrain. The rear axle  137  is not mounted to provide such pivot action. 
     Referring now back to FIG. 12, connected to the front axle  136  is a left-front hydraulic wheel drive motor mounting assembly  148 . A left-front side frame  140  attaches to the frame  100 . Each of the four wheels  112 ,  116 ,  120 ,  124  have a similar construction. A top view of the front axle assembly  136   a  is shown in FIG. 34 and a top view of the rear axle assembly  137   a  is shown in FIG.  35 . 
     Again referring back to FIG. 12, the front axle frame section  138  is located directly over the front axle  136 . The front axle frame section  138  is welded to the left-front side frame  140  and the right-front side frame on the opposite side of the self-propelled rotary excavator  10 . The left front vertical axle guide  142 , as shown in FIG. 12, and the right front vertical axle guide (not shown), along with a left and right rear vertical axle guide prevent forward or backward movement of the front axle  136  while the self-propelled rotary excavator  10  is moving. The rear axle  137  is mounted directly to the machine frame  100  as shown in FIGS. 36 and 37 and thus does not pivot as discussed above. 
     As shown in FIG. 12, the left front hydraulic wheel drive motor mounting assembly  148  is attached to the left side of the front axle  136  and contains the left front wheel hydraulic motor which is connected to the left front wheel  116 , the other wheels are associated with their own hydraulic motors in a similar fashion. 
     Associated with the axle guides are a pair of transport mounting pads. A left front transport mounting pad  150  is secured to the left front vertical axle guide  142  and to the left rear vertical axle guide. Another transport mounting pad is secured to the right front vertical axle guide and the right rear vertical axle guide, in a manner similar to that described above. When the self-propelled rotary excavator  10  is transported, the self-propelled rotary excavator  10  can be supported using the mounting pads  150 . 
     FIG. 13 is a perspective view of the layout of the rotary cutting head hydraulic pump  78  and wheel drive pumps  68 ,  70 ,  72 ,  74  layout as viewed from above the self-propelled rotary excavator  10 , FIG. 1, while looking at an area just in front of the diesel engine  90 . Shown is a drive box mounting bracket  82  attached to the frame assembly  100 . Attached to the drive box mounting bracket  82  is a drive box  80 . Connected to the drive box  80  are a left rear wheel hydraulic pump  68 , a left front wheel hydraulic pump  70 , a right rear wheel hydraulic pump  72 , a right front wheel hydraulic pump  74 , a rotary cutting head hydraulic pump  78  and a drive coupling  76  which attaches to the diesel engine  90 . 
     FIG. 14 is a side view of the layout of the rotary cutting head pump and the wheel drive pumps as shown in FIG.  13 . The drive box mounting bracket  82  is shown attached to the frame assembly  100 . The right rear wheel hydraulic pump  72  and the right front wheel hydraulic pump  74  are shown from the side. 
     FIG. 15 is a perspective view of the layout of the rotary cutting head pump and wheel drive pumps as shown in FIG. 13 while displaying hydraulic tubing connections. Also shown is the valve bank  66  attached to the frame assembly  100 . 
     FIG. 16 is a view of the grated steps  25  and the safety handrail  26  attached to the frame assembly  100 . Also shown is a rear-central frame section  130  of the frame assembly  100 . Attached to the rear-central frame section  130  are the right rear lateral boom vertical guide  46  and the left rear lateral boom vertical guide  48 . 
     FIG. 17 is a front view of the rotary cutting head rotor hub  448  with the rotary cutting head rotor  414  removed, and the rotary cutting head mounting pin  442  is shown. Also shown is the vertical telescopic boom pivot pin  310  which allows the vertical telescopic stationary boom  304  to pivot relative to the lateral telescopic extendable boom  202 . 
     FIG. 18 is a perspective view of the rotary cutting head assembly  400  which displays the rotary cutting head position adjustment turnbuckle  432  and the rotary cutting head hydraulic drive motor  426  and associated gear box  450  attached to the rotary cutting head mounting plate  428 . 
     FIG. 19 is a view of the interior of the cab  20  attached to the frame assembly  100 . FIG. 20 is a view of the sectional valve bank  66  attached to the frame assembly  100 . The sectional valve bank  66  includes the valves necessary to operate the lateral and vertical boom assemblies  200 ,  300  and move the self propelled rotary excavator  10 . FIG. 21 is a view of the self-propelled rotary excavator controls located inside the cab  20 . The controls of FIG. 21 are used to manipulate the boom assemblies  200 ,  300  and the portions of rotary cutting head assembly  400  and other portions of  400  not controlled by the controls shown in FIG.  22  and are thus oriented in that direction. FIG. 22 is a view of further controls within the interior of the cab  20  for manipulating the pumps  68 ,  70 ,  72 ,  74  associated with each of the wheels, the lateral boom deck extension hydraulic cylinder  238  (which positions the lateral boom base mounting assembly  236 ), and the adjustable extension shield  406  and deflector shield  408  of the rotary cutting head assembly  400 . Finally, FIG. 23 illustrates laser controls associated with the laser assembly  500 . 
     The excavation of a ditch  2400  will now be explained with reference to FIG.  24 . As explained in further detail below, the boom assemblies  200 ,  300  and rotary cutting head assembly  400  are positioned at the desired ditch location, and a first portion  2401  of a ditch is created by a single pass of the excavator  10 . The rotary cutting head assembly  400  is then slightly offset from its initial position and a second pass is performed as shown in FIG.  24 . The second pass results in the creation of a second ditch portion  2402  as shown in FIGS. 24 and 25. Next the rotary cutting head assembly  400  is positioned to cut a third ditch portion  2403  at a position centered between and deeper than the first ditch portion  2401  and second ditch portion  2402  as shown in FIG.  26 . All three positions  2401 - 2403  were cut with vertical and lateral laser control. 
     In preferred embodiments, each of the wheel hydraulic pumps  68 ,  70 ,  72  and  74  are a 23 series Sundstrand hydraulic pump. Preferably, the valve bank  66  is a V-42 Gresen sectional valve bank. The drive box  80  is preferably a Funk series 56013. The cutting head hydraulic pump  78  is preferably a 25 series Sundstrand hydraulic pump which is preferably driven at approximately 2,200 r.p.m. with a displacement of 10.12 cubic inches. Likewise, the hydraulic motor at each wheel is a 23 series Sundstrand hydraulic motor. The pumps are driven at approximately 2,200 r.p.m. and the wheel drive gear box ratio is 115: 1 . The displacement of the 23 series Sundstrand hydraulic pump/motor is 5.43 cubic inches. The rotary cutting head hydraulic drive motor  426  is a 24 series Sundstrand hydraulic motor with a displacement of 7.24 cubic inches. All pumps and motors have a 5,000 psi relief valve. The diesel engine  90  is preferably a 318 Detroit diesel engine producing approximately 300 horsepower. 
     In operation, the self-propelled rotary excavator  10  moves in parallel to the side of the ditch being maintained or excavated, as shown in FIGS. 10,  24 ,  25 , and  26 . The cutting of such a ditch is accomplished by the proper control of the lateral telescopic extendable boom assembly  200  connected to a vertical telescopic extendable boom assembly  300  with a rotary cutting head assembly  400  attached to the lower end of the vertical telescopic boom assembly  300 . The lateral and vertical telescopic extendable boom assemblies  200 ,  300  enable the rotary cutting head assembly  400  to be positioned outward from the excavator  10  and downward toward the ground for the purpose of excavating a new ditch or cleaning out silt and debris from an existing ditch, as shown in FIGS. 1,  10 ,  24 ,  25 , and  26 . 
     The function of the lateral telescopic boom assembly  200  is to extend the rotary cutting head assembly  400  outward to the selected cutting position. The lateral telescopic extendable boom  202  is the moveable section of the lateral telescopic boom assembly  200  which fits inside the lateral telescopic stationary boom  204 . The lateral telescopic stationary boom  204  encloses and serves as a guide for the lateral telescopic extendable boom  202 , as shown in FIGS. 1,  2 ,  3  and  6 . 
     The lateral telescopic stationary boom  204  is mounted on a lateral boom base mounting assembly  236 , as shown in FIGS. 7 and 11. The lateral telescopic stationary boom  204  is connected to the lateral boom base mounting assembly  236  through a large pivot pin  248  located at the rear of the lateral telescopic stationary boom  204 . 
     As shown in FIGS. 7 and 11 the lateral boom base mounting assembly  236  is moveable across the top of the self-propelled rotary excavator  10  by a lateral boom deck extension hydraulic cylinder  238 . The lateral boom base mounting assembly  236  is held in position by the lateral boom deck extension guide  244  as shown in FIG.  11 . 
     A lateral telescopic extendable boom hydraulic cylinder  206  extends and retracts the lateral telescopic extendable boom  202  relative to the lateral telescopic stationary boom  204 . Slidably mounted within the lateral telescopic extendable boom hydraulic cylinder  206  is a lateral telescopic extendable boom hydraulic cylinder ram  210 . The lateral telescopic extendable boom hydraulic cylinder ram  210  is connected to the lateral telescopic extendable boom  202  through a lateral telescopic extendable boom hydraulic cylinder ram pin  208 . The lateral telescopic extendable boom hydraulic cylinder ram pin  208  is secured in a lateral telescopic extendable boom hydraulic cylinder ram pin mounting bracket  212 . The lateral telescopic extendable boom hydraulic cylinder ram pin mounting bracket  212  is connected to the lateral telescopic extendable boom  202 . The lateral telescopic extendable boom hydraulic cylinder  206  moves the lateral telescopic extendable boom  202  and rotary cutting head assembly  400  to the selected position for excavation. During excavation, the position of the lateral telescopic extendable boom hydraulic cylinder  206  and the lateral telescopic extendable boom hydraulic cylinder ram  210  may be controlled by the laser alignment control receiver  502  mounted horizontally on top of the vertical boom assembly  300 , as shown in FIGS. 1 and 3. Also included is a lateral boom rest  50 , as shown in FIG.  1 . 
     As shown in FIGS. 2 and 6, the lateral telescopic stationary boom roller  232  is positioned at the bottom of the outward end of the lateral telescopic stationary boom  204 . The lateral telescopic extendable boom  202  extends and retracts with its weight supported by the lateral telescopic stationary boom roller  232 , reducing friction and allowing more freedom of movement. The lateral telescopic stationary boom roller  232  is externally exposed and can be serviced through receptacles on either side of the lateral telescopic boom assembly  200 . 
     The lateral telescopic boom assembly  200  also has a lateral telescopic extendable boom internal roller  234  located at the rear and upper part of the lateral telescopic extendable boom  202 , as shown in FIG.  6 . The lateral telescopic extendable boom internal roller  234  contacts the inside of the upper portion of the lateral telescopic stationary boom  204 . The lateral telescopic extendable boom  202  extends and retracts with its weight reacted by the lateral telescopic extendable boom internal roller  234 . Servicing and inspection ports are located on each side of the lateral telescopic stationary boom  204 . The lateral telescopic extendable boom internal roller  234  can be inspected and serviced by moving the lateral telescopic extendable boom  202  to the position where the internal roller is exposed through the inspection ports located on each side of the lateral telescopic stationary boom  204 . 
     The lateral boom deck extension guide  244  partially encloses and is a guide for the lateral boom deck extension sliding base plate  246  attached to the bottom of the lateral boom base mounting assembly  236 , as shown in FIG.  11 . 
     As shown in FIG. 11, the lateral boom deck extension hydraulic cylinder mounting bracket  240  is mounted on the ram end of the lateral boom deck extension hydraulic cylinder  238 . The lateral boom deck extension hydraulic cylinder mounting bracket  240  is connected to the base of the lateral boom deck extension sliding base plate  246 . 
     As shown in FIGS. 2 and 7, twin lateral boom hydraulic cylinders  216 ,  218  are each connected at one end to the lateral boom base mounting assembly  236  and at the other end to the lateral telescopic stationary boom  204  so as to lift the lateral telescopic stationary boom  204  while the lateral telescopic stationary boom  204  is being moved inward or outward from the self-propelled rotary excavator  10  by the lateral boom deck extension hydraulic cylinder  238 . Each of the twin lateral boom hydraulic cylinders  216  and  218  are connected to the lateral telescopic stationary boom  204  through a lateral boom hydraulic cylinder ram pin  220 , as shown in FIGS. 2 and 7. The purpose of lifting the lateral telescopic stationary boom  204  is to reduce or remove the weight from the lateral boom rest  50 , as shown in FIGS. 1 and 2, when extending or retracting the lateral telescopic stationary boom  204  with the lateral boom base mounting assembly  236 . 
     The lateral telescopic boom assembly  200  is guided vertically by a boom guide  40 , as shown in FIGS. 1,  2 , and  3 . The boom guide  40  serves as a vertical guide and brace for the lateral telescopic boom assembly  200 . The boom guide  40  supports the lateral telescopic boom assembly  200  in the event there are excessive forward or backward forces due to encountering obstacles during the cutting of a ditch. The boom guide  40  also serves as a guide to the lateral boom rest  50 , which elevates and lowers the lateral telescopic stationary boom  204 . The lateral boom rest  50  supports the weight of the lateral telescopic boom assembly  200  while the self-propelled rotary excavator  10  is in the process of excavating, as shown in FIGS. 1 and 2. The boom guide  40  includes a right front lateral boom vertical guide  42 , a left front lateral boom vertical guide  44 , a right rear lateral boom vertical guide  46 , a left rear lateral boom vertical guide  48 , all of which are connected to the frame assembly  100 . A lateral boom rest assembly vertical guide  52  is slidably mounted in between the right front, left front, right rear, and left rear lateral boom vertical guides  42 ,  44 ,  46  and  48 , as shown in FIG.  2 . 
     As shown in FIGS. 1 and 2, a four-stage lateral boom hydraulic cylinder  222  is pivotally connected to the frame  100  at one end and is attached to the lateral boom rest assembly  50  at its other end. The four stage lateral boom hydraulic cylinder  222  is attached to the frame assembly  100  by a four stage lateral boom hydraulic cylinder base pin  224 . A four stage lateral boom hydraulic cylinder shield housing  226  surrounds the four stage lateral boom hydraulic cylinder  222 . The purpose of the four stage lateral boom hydraulic cylinder  222  is to raise, lower and support the lateral telescopic stationary boom  204  while the machine is excavating. The four stage lateral boom hydraulic cylinder  222  controls the elevation of the lateral boom rest  50  which controls the position and supports the lateral telescopic stationary boom  204  during the excavation process. The lateral boom rest  50  is located on top of the four stage lateral boom hydraulic cylinder  222 . The lateral boom rest  50  allows the lateral telescopic stationary boom  204  to rest while the self-propelled rotary excavator  10  is in the process of excavating ditches. During this time, the twin lateral boom hydraulic cylinders  216  and  218  are disengaged and are not functioning. This allows the four stage lateral boom hydraulic cylinder  222  with the lateral boom rest  50  to control the elevation of the lateral telescopic stationary boom  204 . This provides resting support for the lateral telescopic stationary boom  204  near the area of excavation as compared to the twin lateral boom hydraulic cylinders  216 ,  218 . This allows more precise control when elevating and lowering the lateral telescopic stationary boom  204 . With the twin lateral boom hydraulic cylinders  216  and  218  disengaged, the only downward pressure exerted on the rotary cutting head rotor  414  while excavating is the weight of the lateral telescopic boom assembly  200 , the vertical boom assembly  300  and the rotary cutting head assembly  400 . This allows upward movement of the lateral and vertical boom assemblies  300  and  400  and the rotary cutting head rotor  414  in the event an obstruction is encountered while excavating. 
     As shown in FIGS. 2,  3   8 , and  28   a, b, c , a lateral telescopic extendable boom hydraulic hose grouping assembly support  214  connects to both the lateral telescopic extendable boom  202  and the lateral telescopic stationary boom  204 . The lateral telescopic extendable boom hydraulic hose grouping assembly support  214  is connected to the lateral telescopic extendable boom  202  via a hose grouping assembly frontal pin and mounting bracket  228 , as shown in FIG. 2. A hose grouping assembly rear pin and mounting bracket  230  connects the lateral telescopic extendable boom hydraulic hose grouping assembly support  214  to the lateral telescopic stationary boom  204 . The lateral telescopic extendable boom hydraulic hose grouping assembly support  214  raises and lowers the hydraulic hoses when the lateral telescopic extendable boom  202  is retracted and extended, respectively. The lateral telescopic extendable boom hydraulic hose grouping assembly support  214  moves downward with the extension of the lateral telescopic extendable boom  202 . As the lateral telescopic extendable boom  202  is retracted, the lateral telescopic extendable boom hydraulic hose grouping assembly support  214  raises the hoses away from moving parts. This prevents the hoses from being entangled and damaged. As the lateral telescopic extendable boom  202  moves outward the lateral telescopic extendable boom hydraulic hose grouping assembly support  214  is lowered and allows the hoses to extend with the lateral telescopic extendable boom  202 . As the lateral telescopic extendable boom  202  moves inward, the hoses are again lifted out of the way of the moving machinery. The position of the lateral telescopic extendable boom hydraulic hose grouping assembly support  214  is also used as a steering indicator guide by the operator when the self-propelled rotary excavator  10  is operating and excavating. The position of the lateral telescopic extendable boom hydraulic hose grouping assembly support  214  is used as a visual guide for steering the self-propelled rotary excavator  10 . 
     The cab  20  is conveniently located on the frame assembly  100  to enable the operator to comfortably watch the area of excavation, as shown in FIGS. 1,  3 , and  19 . The cab is attached to the frame assembly  100  at the frontal cab supporting base  24 . From such a location the operator can view other working components. The position of the cab  20  also helps to provide for the safety and comfort of the operator. The frame of the cab  20  is constructed from steel tubing and sheet metal, so as to provide ample protection for the operator. The windows are constructed of heavy safety glass panels. 
     The front and right side windows of the cab  20  have heavy screens  22  to give protection from flying debris or other excavated materials. The screens are mounted in frames that are attached to the cab  20  by hinges and pins. The pins may be pulled and the screens may be opened for window cleaning. 
     The upper hinged rear window  30 , as shown in FIG. 10, is hinged to the cab  20  so that it may be opened for added operator comfort. The upper hinged rear window  30  can be held in a selected position by air support cylinders. The upper hinged rear window  30  can also be used as a secondary exit over the right rear fender  108 . 
     The cab  20  has a conventional steel side door  32  with a glass panel and a securing latch, as shown in FIG.  10 . 
     Inside the cab  20  is located the operational controls of the self-propelled rotary excavator  10  along with laser controls, as shown in FIGS. 19,  21 ,  22  and  23 . The operational controls include a safety “kill” switch for immediate engine  90  shut down, should the need arise. This switch is conveniently located on the floor of the cab near the door. 
     The exhaust pipes of the diesel engine  90  are surrounded by expanded steel muffler safety shields  92 , as shown in FIG. 1. A safety handrail  26  attached to the frame assembly  100  is shown in FIG.  2 . The safety handrail  26  is mounted on the front of the cab  20  above the grated steps  25 . The handrail gives hand support to the top of the grated deck floor. The grated steps  25  are conveniently located in front of the cab  20 . 
     The hydraulic fluid reservoir  60  is mounted on the front vehicle frame beam  104 . The hydraulic fluid reservoir  60  can retain up to 350 gallons of hydraulic fluid. The interior of the hydraulic fluid reservoir  60  contains circulation baffles. 
     A hydraulic fluid cooler  62  is mounted adjacent to the diesel engine  90  and on the front vehicle frame beam  104 . 
     The priority flow regulator valves  64 , as shown in FIG. 10, convert an open center hydraulic system through a closed center hydraulic system. The valves are driven by proportional time output of the control box. The priority flow regulator valves  64  are necessary to produce a smooth laser response when the lasers are in operation. 
     The hydraulic mechanisms are remotely controlled with a joy stick in the cab  20 . The valves are electromechanical proportional hydraulic pilot type valves. A bank of V-42 Gresen valves (valve bank  66 ) is shown in FIGS. 15 and 20. 
     The laser alignment control receiver  502  or the laser receiver  508  can be independently disengaged to allow the performance of the separate functions as determined by the operator, as shown in FIG.  1 . 
     The laser alignment control receiver  502  of the laser equipment  500  can be disengaged so as to allow the operator to make curves in the ditch and still maintain the same ditch bottom elevation. The laser receiver  508  can be turned off to allow the operator to excavate deeper cuts to establish silt traps at water furrow junctions and near the area of pipe drops. 
     The operator may disengage the vertical telescopic boom pendulous sensing device  306  which controls the vertical position of the vertical boom assembly  300  via the vertical telescopic boom positioning control cylinder  312 . The vertical telescopic boom position control cylinder  312  is rotatably connected at one end to the lateral telescopic extendable boom  202  and its other end it is connected to a vertical telescopic boom position control cylinder adjustable pivot pin mounting bracket  314 . The vertical telescopic boom position control cylinder adjustable pivot pin mounting bracket  314  is in turn connected to the vertical telescopic stationary boom  304 . 
     Such a device allows the operator to use the vertical telescopic boom position control cylinder  312  to make sweeping cuts for wider ditch excavations near a pipe drop or outflow pipe. 
     The vertical telescopic boom pendulous sensing device  306  is mounted on the front of the vertical telescopic stationary boom  304 . The vertical telescopic boom pendulous sensing device  306  detects the side tilt of the vertical telescopic stationary boom  304 . Any deviation from zero tilt sends a signal from the vertical telescopic boom pendulous sensing device  306  to a control unit in the cab  20  that will in turn send a signal to the control valve to correct the vertical telescopic boom position control cylinder  312  so as to attain the correct vertical telescopic stationary boom  304  position. 
     Quick release hydraulic hose coupler connectors  316  are shown in FIG.  2 . The quick release hydraulic hose coupler connectors  316  are used to disconnect the hydraulic hoses when preparing the self-propelled rotary excavator  10  for transport and when replacing the outer hydraulic hoses when needed. 
     A vertical boom lifting bracket  318  is connected to the vertical telescopic stationary boom  304 , as shown in FIG.  2 . The vertical boom lifting bracket  318  is used for attaching lifting cables when the vertical boom assembly  300 , the rotary cutting head assembly  400  and the lateral telescopic extendable boom  202  are being removed from the machine for transport. 
     The laser alignment control receiver  502  is mounted horizontally on top and over the vertical boom assembly  300 , as shown in FIGS. 1,  3 ,  8   10  and  25 . The laser alignment control receiver  502  detects the plane of light established by the laser transmitter  514 , as shown in FIGS. 24,  25  and  26 . A signal is sent from the laser alignment control receiver  502  to the control box mounted in the cab  20 , as shown in FIG. 23, the signal being indicative of the relative position of the laser signal to the plane of light. The control box sends a signal to the horizontal boom cylinder&#39;s control valve commanding hydraulic movement of the lateral telescopic extendable boom hydraulic cylinder&#39;s ram  210  to keep the laser alignment control receiver  502  centered in the plane of light in the correct horizontal position. 
     A vertical sensing depth control laser receiver  508  and laser receiver mount  510  are mounted vertically on the base of the vertical telescopic extendable boom  302 . The laser receiver  508  detects the plane of light established by the laser transmitter  514 . A signal produced by the laser receiver  508  is sent to the laser control box mounted in the cab  20 , as shown in FIG. 23, which is indicative of the relative position of the laser receiver  508  relative to the plane of light. The laser control box sends a signal to the vertical boom cylinder&#39;s control valve commanding hydraulic movement of the vertical telescopic boom hydraulic cylinder  320  and ram  322  to keep the laser receiver  508  centered in the plane of light and on a grade. 
     The rotary cutting head assembly  400  includes a rotary cutting head shield  402  which partially encloses the rotary cutting head rotor  414 . The rotary cutting head shield  402  contains the spoil material as it is cut and removed from the soil surface and set in motion. The rotary cutting head shield  402  then directs the excavated material to a controlled point of departure through the shield outlet. The rotary cutting head shield  402  also protects the self-propelled rotary excavator  10  from excavated material by directing the flow of this material through the rotary cutting head shield outlet  409  away from the self-propelled rotary excavator  10 . 
     The rotary cutting head shield  402  has mounted to it, as a forward extension, a rotary cutting head frontal extension shield  404 . The rotary cutting head frontal extension shield  404  prevents excavated material from moving forward and directs it back toward the area of the rotary cutting head rotor  414  where it will be set in motion and expelled through the outlet of the rotary cutting head shield  402 . The rotary cutting head frontal extension shield  404  bolts onto the rotary cutting head shield  402  and also serves as a structural brace for the rotary cutting head shield  402 , as shown in FIG.  3 . 
     The rotary cutting head assembly  400  further includes a rotary cutting head adjustable extension shield  406  which is mounted on the rotary cutting head shield  402 . The rotary cutting head adjustable extension shield  406  is extended when making excavations less than one-half the diameter of the rotary cutting head. The rotary cutting head adjustable extension shield cylinder  412  extends the rotary cutting head adjustable extension shield  406  downward as material is excavated from shallow cuts. The rotary cutting head adjustable extension shield  406  prevents excavated material from moving toward the self-propelled rotary excavator  10  and laser equipment  500  when making a shallow cut and directs the excavated material through the cutting head shield outlet away from the machine. The rotary cutting head adjustable extension shield  406  is utilized when the rotor is excavating shallow depths clockwise or counter-clockwise as shown in FIGS. 3,  29   a  and  29   b.    
     The rotary cutting head adjustable extension shield  406  is actuated by a rotary cutting head adjustable extension shield cylinder  412 . One end of the rotary cutting head adjustable extension shield cylinder  412  is connected to the rotary cutting head adjustable extension shield  406  and the other end is connected to a mounting bracket on the rotary cutting head shield  402 , as shown in FIGS. 3,  29   a  and  29   b.    
     The rotary cutting head assembly  400  is also equipped with a rotary cutting head adjustable deflector shield  408 , as shown in FIG.  4 . The rotary cutting head adjustable deflector shield  408  is actuated by a rotary cutting head adjustable deflector shield hydraulic cylinder  410  so as to adjust the deflection of the spoil material and which controls the elevation of the spoil material as it exits the outlet of the rotary cutting head shield  402 . The rotary cutting head adjustable deflector shield  408  also helps to direct the outflowing spoil into the field away from the self-propelled rotary excavator  10  and away from the laser receivers  502  and  508  located above the rotary cutting head rotor  414 . The rotary cutting head adjustable deflector shield hydraulic cylinder  410  is connected at one end to the rotary cutting head adjustable deflector shield  408  and the other end is connected to a mounting bracket attached to the rotary cutting head shield  402 . 
     Rotary cutting head blade mounting brackets  420  are located on the rotary cutting head rotor  414 . Rotary cutting head rotor impeller blades  416  fit across the end of the rotary cutting head blade mounting brackets  420 . The rotary cutting head rotor impeller blades  416  have the same forward curved cutting edge as the rotary cutting head rotor blades  418 . The rotary cutting head rotor impeller blades  416  also have a hard surface on the forward edge of the cutting side. The rotary cutting head rotor impeller blades  416  are used with a four rotor cutting blade configuration. The rotary cutting head rotor impeller blades  416  are mounted on alternate rotary cutting head blade mounting brackets  420 . 
     Rotary cutting head rotor blades  418  are rectangular, heavy, steel blades with a forward curved sharpened cutting edge having a hard surface on the forward cutting side, as shown in FIGS. 4,  31  and  32 . The rotary cutting head rotor blades  418  are mounted lengthwise and bolted to the rotary cutting head blade mounting brackets  420 , as shown in FIGS. 4,  31  and  32 . 
     A rotary cutting head central reversible blade  422  is mounted on the front and center of the rotary cutting head rotor  414 , as shown in FIGS. 4,  31  and  32 . The rotary cutting head central reversible blade  422  is sharpened with the cutting edge rotating toward the surface to be cut. The rotary cutting head central reversible blade  422  is a reversible blade. When reversing the direction of rotation, the rotary cutting head central reversible blade  422  can be removed, the ends reversed, and reinstalled and bolted back in place. By reversing the ends, it will change the direction of the cut. 
     A rotary cutting head hydraulic drive motor  426  is used to convert the hydraulic power into mechanical rotary power, as shown in FIGS. 8 and 9. The rotary cutting head hydraulic drive motor  426  is attached to a hydraulic motor drive gear box  450 , as shown in FIG.  18 . The rotary cutting head hydraulic drive motor gear box  450  is 6-K Heco gear box. The rotary cutting head hydraulic drive motor  426  has a 5,000 pound per square inch relief valve. 
     The rotary cutting head mounting plate  428  is used to connect the rotary cutting head hydraulic drive motor  426  to the rotary cutting head shield housing  430 . The rotary cutting head mounting plate  428  is circular and is connected to the bottom of the vertical telescopic extendable boom  302  by the rotary cutting head boom mounting bracket  444  and the rotary cutting head mounting pin  442 , as shown in FIGS. 9 and 18. 
     A rotary cutting head position adjustment turnbuckle  432  is provided so as to position the rotary cutting head assembly  400  about the rotary cutting head mounting pin  442 . The rotary cutting head position adjustment turnbuckle  432  is connected to the rotary cutting head mounting plate  428  by way of the turnbuckle base pin mounting bracket  436  and the turnbuckle base pin  434 . The upper end of the rotary cutting head position adjustment turnbuckle  432  is connected to the turnbuckle outer pin mounting bracket  440  and the turnbuckle outer pin  438 , as shown in FIG.  9 . Turning the rotary cutting head position adjustment turnbuckle  432  in an extension rotation will move the rotary cutting head assembly  400  forward. Rotating the rotary cutting head position adjustment turnbuckle  432  so as to retract its length will cause the rotary cutting head assembly  400  to move towards the rear of the self-propelled rotary excavator  10 . Any retracting or extending movement will be pivoted on the rotary cutting head mounting pin  442 . 
     The rotary cutting head assembly  400  is provided with rotary cutting head hydraulic hose quick coupler connectors  446 , as shown in FIG.  8 . The primary purpose of these rotary cutting head hydraulic hose quick coupler connectors  446  are to disconnect the hoses when the self-propelled rotary excavator  10  is to be transported to another location. By disconnecting the hoses, the rotary cutting head assembly  400 , vertical boom assembly  300  and the lateral telescopic extendable boom  202  can be removed from the self-propelled rotary excavator  10  so as to reduce the transporting width of the self-propelled rotary excavator  10 . The rotary cutting head hydraulic hose quick coupler connectors  446  may be useful in the event there is any need for replacement of hoses in the area of the rotary cutting head rotor  414 . 
     In operation, the rotary cutting head assembly  400  is placed and held at the proper depth and aligned in position by a vertical telescopic extendable boom  302  extending downward from the end of the lateral telescopic extendable boom  202  that extends laterally from the side of the self-propelled rotary excavator  10 . 
     The lateral telescopic extendable boom  202  is moved lateral out from the self-propelled rotary excavator  10  by the lateral telescopic extendable boom hydraulic cylinder  206 , as shown in FIG.  1 . The lateral telescopic extendable boom  202  can be further extended by another hydraulic cylinder that can move the lateral telescopic boom assembly  200  on a track across the upper central machine frame, as discussed earlier and shown in FIG.  11 . 
     Attached to the lateral telescopic extendable boom  202  is the vertical telescopic stationary boom  304 . The vertical telescopic extendable boom  302  is moved vertically by the vertical telescopic boom hydraulic cylinder  320 , as shown in FIG.  8 . The ram end of the vertical telescopic boom hydraulic cylinder  320  is attached to the vertical telescopic extendable boom  302  which is the moveable section of the vertical boom assembly  300  and the base end of the vertical telescopic boom hydraulic cylinder  320  being attached to the vertical telescopic stationary boom or stationary section  304 . 
     Attached to the lower end of the vertical telescopic extendable boom  302  is a rotary cutting device known as the rotary cutting head assembly  400 . 
     The cutting depth and position of the rotary cutting head assembly  400  is determined by the vertical and lateral position of the vertical telescopic extendable boom  302 . Another hydraulic cylinder called the vertical telescopic boom position control cylinder  312  is attached, at an angle, to the vertical telescopic stationary boom  304  and the lateral telescopic extendable boom  202 , as shown in FIG.  3 . The vertical telescopic boom position control cylinder  312  moves the rotary cutting head rotor  414  laterally in a sweeping movement independent of the lateral telescopic extendable boom  202 . 
     The combination and configuration of the lateral and vertical telescopic boom assemblies  200  and  300  give the operator the ability to use lasers for precise ditch alignment and depth control when excavating. The operator has the option to excavate new or maintain existing ditches to a selected grade regardless of the unevenness of the terrain. 
     The laser receiver  508  and the laser receiver mount  510  are mounted vertically on the base of the vertical telescopic extendable boom  302 . The laser receiver  508  detects the plane of light established by the laser transmitter  514 , as shown in FIGS. 3 and 26. The laser receiver  508  sends a signal to the laser control box mounted in the cab  20  as to the relative position of the laser receiver  508  to the plane of light, as shown in FIG.  23 . The control box sends a signal to the control valve of the vertical telescopic boom hydraulic cylinder  320  commanding hydraulic movement of the vertical telescopic boom hydraulic cylinder ram  322  so as to keep the laser receiver  508  centered in the plane of light and on grade. 
     The laser alignment control receiver  502  is mounted on the laser alignment control receiver position adjustment tube  506  on top of and over the vertical telescopic extendable boom  302 , as shown in FIG.  1 . The laser alignment control receiver  502  detects the plane of light established by the laser transmitter  514 , shown in FIG.  25 . The laser alignment control receiver  502  sends a signal to the control box mounted in the cab  20 , as to the relative position of the laser alignment control receiver  502  to the plane of light, as shown in FIG.  23 . The control box sends a signal to the control valve of the lateral telescopic extendable boom hydraulic cylinder  206  commanding hydraulic movement of the lateral telescopic extendable boom hydraulic cylinder ram  210  so as to keep the laser alignment control receiver  502  centered in the plane of light in the correct horizontal position. 
     The position of the laser alignment control receiver  502  can be adjusted horizontally on the laser alignment control receiver position adjustment tube  506  when making multiple parallel cuts while excavating or maintaining large drainage ditches. Adjusting the position of the laser alignment control receiver  502  on the self-propelled rotary excavator  10  saves time since the laser transmitter  514  may remain in a fixed location, otherwise, the position of the laser alignment control receiver  502  would remain constant and the location of the laser transmitter  514  would be changed. A horizontally mounted electric telescopic mast can replace the laser alignment control receiver position adjustment tube  506  in the event numerous multiple parallel cuts would justify the added expense. Such a modification would allow the operator to quickly make horizontal adjustments of the laser alignment control receiver  502  from the cab  20  of the self-propelled rotary excavator  10 . 
     A vertical telescopic boom pendulous sensing device  306  is mounted on the front of the vertical telescopic stationary boom  304 , as shown in FIG.  3 . The vertical telescopic boom pendulous sensing device  306  detects the side tilt of the vertical boom assembly  300 . 
     When the vertical boom assembly  300  is not in a vertical position the vertical telescopic boom pendulous sensing device  306  sends a signal to a control unit in the cab  20  that will in turn send a signal to a control valve to adjust the vertical telescopic boom position control cylinder  312  so as to attain a vertical boom position as shown in FIGS. 1 and 3. 
     The laser alignment control receiver  502  or the laser receiver  508  can be independently disengaged so as to allow the operator to determine separately the functions of the vertical boom assembly  300  and the lateral telescopic boom assembly  200 . 
     As an example, the laser alignment control receiver  502  can be disengaged, thus allowing the operator to manually steer the self-propelled rotary excavator  10  to place a curve in the ditch while maintaining precise laser control of the bottom elevation of the ditch. Likewise, the laser receiver  508  can be disengaged so as to allow the operator to excavate deeper cuts so as to establish silt traps at water furrow junctions or in the vicinity of pipe drops. 
     The operator may utilize the vertical telescopic boom position control cylinder  312  to make sweeping cuts for wider ditch excavations. In such cases, it is necessary to disengage the vertical telescopic boom pendulous sensing device  306  as it controls the position of the vertical telescopic boom position control cylinder  312 . 
     The rotary cutting head assembly  400  is mounted to the lower end of the vertical telescopic extendable boom  302 , as shown in FIGS. 1,  3 ,  4 ,  5 ,  8  and  9 . A rotary cutting head boom mounting bracket  444  attached to the lower end of the vertical telescopic extendable boom  302  is connected by the large rotary cutting head mounting pin  442  to a heavy, vertically mounted, circular steel plate, known as the rotary cutting head mounting plate  428 , on which the rotary cutting head assembly  400  is mounted, as shown in FIG.  9 . The pin, called the rotary cutting head mounting pin  442 , is a hinge or pivot pin which allows adjustment of the position of the rotary cutting head rotor  414  turning the rotary cutting head position adjustment turnbuckle  432 , as shown in FIGS. 8 and 9. 
     The rotary cutting head hydraulic drive motor gear box  450  is attached to the rotary cutting head mounting plate  428 . The rotary cutting head hydraulic drive motor  426  is attached to the rear of the rotary cutting head hydraulic drive motor gear box  450 . 
     A splined drive shaft from the rotary cutting head hydraulic drive motor gear box  450  extends forward through an opening in the rotary cutting head mounting plate  428 . A splined hub, called the rotary cutting head rotor hub  448 , is attached to the splined drive shaft, as shown in FIG.  17 . The rotary cutting head rotor  414  is attached to the rotary cutting head rotor hub  448 . 
     The rotary cutting head rotor  414  is a large heavy circular plate with eight rotary cutting head blade mounting brackets  420  attached to the forward side, as shown in FIGS. 3 and 4. The rotary cutting head blade mounting brackets  420  have holes so as to mount the rotary cutting head rotor blades  418  on the front side of the rotary cutting head rotor  414  or to mount rotary cutting head rotor impeller blades  416  on the end of the rotary cutting head blade mounting brackets  420 . The rotary cutting head rotor impeller blades  416  and the rotary cutting head rotor blades  418  may be mounted on either side of the rotary cutting head blade mounting brackets  420  for clockwise or counterclockwise excavation, as shown in FIGS. 3,  4 ,  5 ,  8 ,  9 ,  31  and  32 . 
     When excavating with the rotary cutting head rotor  414  moving in a counterclockwise direction, the rotary cutting head counter rotation deflector shield  424  should be installed, as shown in FIGS. 8 and 9. The rotary cutting head counter rotation deflector shield  424  is bolted to the inside of the rotary cutting head shield  402  so as to prevent the spoil material from recycling around the rotary cutting head rotor  414  and as such prevents the spoil material from accumulating in the rotary cutting head shield  402  by deflecting the spoil material away from the rotary cutting head rotor  414 . 
     The rotary cutting head rotor  414  has eight rotary cutting head blade mounting brackets  420  attached to the forward side of the rotary cutting head rotor  414  which provide a choice of several blade configurations. Depending on the direction of rotation of the rotary cutting head rotor  414 , the rotary cutting head rotor blades  418  and the rotary cutting head rotor impeller blades  416  can be mounted on either side of the rotary cutting head blade mounting brackets  420 . 
     The cutting component of the rotary cutting head assembly  400  is the rotary cutting head rotor  414 . Because of variable soil and moisture conditions, it is desirable to have a choice of several blade configurations. Depending on the soil and moisture conditions, the type of blades and the number of blades to be mounted on the rotary cutting head rotor  414  can be selected for use in making the most efficient cut. The more efficient configurations are to use four or eight rotary cutting head rotor blades  418 . When using four rotary cutting head rotor blades  418 , the rotary cutting head rotor impeller blades  416  can be used on the alternate rotary cutting head blade mounting brackets  420 . Such a configuration can be used on the rotary cutting head rotor  414  as operating in either a clockwise or counterclockwise direction. 
     The rotary cutting head rotor  414  is driven with sufficient power and with a continuous and adequate speed so as to excavate new field drainage ditches and lateral drainage ditches when using either blade configuration. Both types of ditches can be excavated to a sufficient size with the proper bottom grade so as to quickly remove excess amounts of water from the field to be drained. 
     The self-propelled rotary excavator  10  has the ability to maneuver over undulating fields and uneven ground. The self-propelled rotary excavator  10  has the ability to work along the side of a bank or the side slope of a road. When the self-propelled rotary excavator  10  works along a slope, it continues to maintain a vertical boom position which give the machine the ability to excavate a straight and uniformly graded ditch. 
     The self-propelled rotary excavator  10  has a wide, sturdy frame, as shown in FIGS. 1 and 25. The component parts of the self-propelled rotary excavator  10  are arranged and placed in areas on the frame assembly  100  so as to help counterbalance the weight of the boom assemblies  200  and  300  when they are extended, as shown in FIGS. 1,  10  and  25 . 
     The self-propelled rotary excavator  10  is a four wheel drive vehicle, since each wheel is associated with its own hydraulic pump and hydraulic motor system. The self-propelled rotary excavator  10  has large rubber tires having adequate flotation for use in moderately wet field conditions. The self-propelled rotary excavator  10  is hydraulically driven to propel itself at a given speed independent of other machine functions. 
     The rear axle of the self-propelled rotary excavator  10  is connected directly to its frame. Such a connection adds stability to the self-propelled rotary excavator  10  when extending and withdrawing the lateral and vertical telescopic boom assemblies  200  and  300  during operation. The front axle  136  is connected to the front axle frame section  138  of the self-propelled rotary excavator  10  by the front axle hinge pin  146  that allows the front wheels  112  and  116  to move vertically when traveling over uneven terrain. 
     The directional control or steering of the self-propelled rotary excavator  10  is by a method called “skid steering”. The rotation of the wheels on the left side of the self-propelled rotary excavator  10  are synchronized and the rotation of the wheels on the right side of the machine are also synchronized. The self-propelled rotary excavator  10  turns by commanding the wheels on one side of the self-propelled rotary excavator  10  to move at a different rate of speed than the wheels on the opposite side. Such a steering mechanism imparts the ability to make very minute correctional turns while the self-propelled rotary excavator  10  is in operation. 
     The self-propelled rotary excavator  10  is able to clean and maintain to grade existing field ditches while, simultaneously, spreading the spoil material evenly. 
     The self-propelled rotary excavator  10  can vary the rotary cutting head speed and the ground speed independently of the other machine functions. Such a separation of the functions of the components gives the operator the necessary options for selecting the proper combination of parameters so as to perform the most efficient work. 
     Spoil material ejected from the self-propelled rotary excavator  10  is broken into small particles and distributed evenly as a thin layer that does not block natural drainage or existing field water furrows. Furthermore, silt deposited into the ditch by field erosion is thinly spread back over the field to the area from which most of it originated by operation of the self-propelled rotary excavator  10 . Such small particles of spoil dry quickly when exposed to air and sunlight. After the spoil material dries, rain will soften and further pulverize this material into smaller particles which will easily blend back into the top soil. 
     The evenly distributed spoil material allows for normal farming operations, such as field preparation or crop cultivation, which can follow the ditching operation without any special tillage treatment to the area in which the spoil material was deposited. 
     The most efficient and productive time over the year to use any excavating equipment is when the soil is dry. Historically, soil is usually the driest during the late spring, summer and early fall months. However, such times of the year are during the planting, growing and harvesting seasons. 
     This is not always a limitation to the self-propelled rotary excavator  10  since crop damage from ditch maintenance by the self-propelled rotary excavator  10  in most young growing crops is usually much less than the yield losses sustained following ditch maintenance by a hydraulic trackhoe and dozer done under wet soil conditions prior to planting the crop. Furthermore, hydraulic trackhoes and dozers are not able to utilize the spring, summer and early fall months since they severely damage or destroy a growing crop in the area of their work. 
     The self-propelled rotary excavator  10  is able to perform the ditch maintenance during the growing season while imparting very little damage to the growing crop. Such a reduction in the damage to the growing crop can be accomplished by reducing the size of the spoil particles and lowering their impact velocity. 
     The spoil particle size can be regulated by selecting a suitable forward speed of the self-propelled rotary excavator  10 , using the appropriate motor speed and using a selected number of cutting blades to match the condition of the soil. 
     Counter rotating the rotary cutting head rotor  414  results in the spoil particles being lofted or elevated which reduces their lateral velocity. 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

Summary:
A self-propelled rotary excavator having a plurality of booms forming a boom assembly attached to a chassis, with a rotary cutting device attached to the end of the boom assembly. The boom assembly positions the rotary cutting device at a desired position in regard to the chassis or moving portion of the self-propelled rotary excavator. The position of the rotary cutting device is maintainable (preferably controlled by lasers) so as to provide a ditch which has a constant grade regardless of the undulations of the land upon which the self-propelled rotary excavator traverses. An operator of the self-propelled rotary excavator can also independently control both the depth of the cut produced by the rotary cutting device and the distance in a direction perpendicular to the depth of the cut produced by the rotary cutting device. Such independent control of the boom assembly allows the operator of the self-propelled rotary excavator to provide a ditch which is capable of avoiding large objects which may damage the rotary cutting device or the operator may produce a special cut in the ditch such as a localized deep portion so as to act as a silt accumulator. Thus, the self-propelled rotary excavator provides a cutting device which is capable of cutting deeply into the soil to provide a deep drainage ditch, while operating over rough terrain.