Abstract:
A self propelled sprinkler is disclosed. The sprinkler has a support body with a drive unit which drives two rear wheels. The drive unit is powered by water pressure supplied through a hose which is coupled to the drive unit via a hose coupler. The drive unit has a cylindrical drive chamber with circular impeller in fluid communication with the hose coupler. The impeller is rotated by the water pressure and is mechanically connected to a lateral shaft. The shaft is connected to the rear wheels. Reduction gearing from the impeller to the shaft governs the speed of the sprinkler. The reduction gearing is achieved through a series of sun gears, carrier disks and planet gears. The drive unit also has an outlet which has a socket which allows the exit of the pressurized water. The socket allows the insertion of any variety of sprinkler heads. Thus, the sprinkler allows a variety of water distribution patterns. The sprinkler is propelled by water pressure rotating the impeller and eventually the rear wheels.

Description:
FIELD OF INVENTION 
     This invention relates to a self propelled irrigation sprinkler. More specifically, this invention relates to an impeller driven sprinkler which traverses an area to be watered. 
     BACKGROUND OF INVENTION 
     It is often desirable to water large areas of a lawn. One common method to accomplish this aim is installation of underground pipes with sprinklers which are placed to insure that all areas of the lawn have coverage. This method is effective, however it is expensive and time consuming to install the pipes and sprinklers in the ground. Furthermore, it is difficult to change the location of sprinklers should various features of the area change. 
     Another inexpensive method for watering a lawn area involves using a garden hose with a sprinkler. The sprinkler is fluidly driven and distributes water in a designed geometric pattern. Examples of sprinklers include an oscillator arm sprinkler type or a spray pattern irrigation device. The garden hose is connected to a spigot which supplies water to the sprinkler under pressure. The proportion of the water flow from the spigot may be regulated by turning a knob. 
     A user typically connects one end of the hose to the spigot, attaches the sprinkler to the other end of the hose and places the sprinkler in the area desired to be watered. The user then turns on the water flow from the spigot by turning the knob. The water flow is forced through the hose and distributed by the sprinkler to the desired area. In this manner, areas which are distant from the spigot may be watered. By regulating the flow rate from the spigot, the user may also alter the speed of the sprinkler and the distance it throws water in the area. After the sprinkler is set up in the desired location, the user is free to attend to other tasks while the area is watered. 
     This method provides an inexpensive alternative to a permanent irrigation system as a user may move the sprinkler to the areas where watering is needed. However, compared to permanent irrigation systems, this method is much more labor intensive, especially for large areas. One solution which has been proposed for areas which are too large to be irrigated with one fixed sprinkler is a wheeled sprinkler which is self propelled and reels in hose as it travels across an area toward the spigot. Such a sprinkler uses the water pressure to turn a rotating sprinkler head and uses this rotational force to propel the wheels of the sprinkler. Reduction gearing connected to the sprinkler head is attached to the wheels to achieve a relatively slow speed to insure proper watering of the area. This sprinkler head has a pair of arms which rotate and discharge water at their ends thus creating coverage over a certain defined width along the path of the sprinkler. Unfortunately, such sprinklers suffer from the inability to water irregularly shaped areas since the rotating sprinkler head can only water in one circular pattern. 
     Thus, there exists a need for a self propelled sprinkler which allows watering of large areas using an efficient propulsion means. There also exists a need for a self propelled sprinkler which provides the use of different spray heads independent of the propulsion of the sprinkler. There is also a need for a self propelled sprinkler which follows a hose for its path. 
     SUMMARY OF THE INVENTION 
     These needs and others may be met by the present invention which is embodied in a self propelled sprinkler unit for irrigation of a ground area and connection with a hose connected to a pressurized water source. The sprinkler unit has a drive unit having a hose inlet with a hose coupler. The drive unit having a drive chamber with a rotatable impeller in fluid contact with the water flow from the hose inlet. A shaft is mechanically coupled to the impeller. The sprinkler unit has a pair of rear wheels with at least one rear wheel coupled to the shaft. An outlet coupler is in fluid communication with the drive unit. A sprinkler head is coupled to the outlet coupler. 
     The invention may also be embodied in a water propelled drive unit for a self propelled sprinkler with a hose coupled to a water source. The drive unit has an enclosed drive chamber with a cylindrical shape having two relatively flat ends, an outer surface, and an inner surface. An inlet coupler is located on the exterior surface of the drive chamber allowing fluid communication to the drive chamber. A shaft is mounted between the two flat ends. A rotatable impeller is mounted axially on the shaft in the drive chamber. The impeller is in fluid contact with the inlet coupler and is rotatably coupled to the shaft. An outlet coupler is mounted on the exterior surface of the drive chamber. 
    
    
     It is to be understood that both the foregoing general description and the following detailed description are not limiting but are intended to provide further explanation of the invention claimed. The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the invention. Together with the description, the drawings serve to explain the principles of the invention. 
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view of the traveling sprinkler according to one embodiment of the present invention. 
     FIGS. 2A &amp; 2B are an exploded perspective diagram of the traveling sprinkler of FIG.  1 . 
     FIG. 3 is a top cutaway view of the impeller motor of the traveling sprinkler of FIG.  1 . 
     FIG. 4 is a side cutaway view of the impeller motor of the traveling sprinkler of FIG.  1 . 
     FIG. 5A-5F are close up perspective views of different sprinkler heads which are installed on the traveling sprinkler of FIG.  1 . 
     FIG. 6 is a perspective view of a traveling sprinkler according to another embodiment of the present invention. 
     FIG. 7 is a cutaway view of the traveling sprinkler in FIG. 6 
     FIG. 8 is a top view of another embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the present invention is capable of embodiment in various forms, there is shown in the drawings and will hereinafter be described different embodiments with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiments illustrated. 
     FIG. 1 is a perspective view of a traveling sprinkler  10  and FIG. 2A and 2B are an exploded view of the parts of the traveling sprinkler  10 . The traveling sprinkler  10  has a main body  12  with two large rear wheels  14  and  16  and two front wheels  18  and  20 . The main body  12  is preferably fabricated from plastic although metal may be used. The main body  12  is fabricated in an aesthetically attractive shape such as in a tractor model shape in this example. Of course other shapes such as an automobile, paddle boat, spaceship etc. may be used for the main body  12 . The rear wheels  14  and  16  have relatively large track width and corresponding surface contact area in order to obtain better traction. The main body  12  has a front end  22  and a rear end  24 . The rear end  24  has a hose connector  26  which may be coupled to a garden hose  28  and which supplies pressurized water to the traveling sprinkler  10 . A sprinkler unit  30  is mounted on a top surface  32  of the main body  12 . The sprinkler unit  30  as will be explained below is an impact type sprinkler, although any other sprinkler head such as a pair of rotating arms, rotor, etc. may be used. 
     The front wheels  18  and  20  are mounted on a rotating clevis  34 . The rotating clevis  34  has a pair of forks  36  and  38  which end in coupler sockets  40  and  42  respectively. The front wheels  18  and  20  are preferably fabricated from hard plastic which may be snapped into the forks  36  and  38 . Of course other configurations such as an axle may be used for holding the front wheels  18  and  20 . The rear wheels  14  and  16  are preferably made of hard plastic and have an exterior contact surface  44  with a series of nubs  46  which are molded on the contact surface  44  in order to improve traction on the ground. A water based drive unit  50  is fluidly connected to the hose  28  and provides water propulsion for the rear wheel  14  and the sprinkler head  30 . 
     The interior of the traveling sprinkler  10  will be explained with reference to FIGS. 2A and 2B and FIGS. 3-4 which are top and side cutaway views of the drive unit  50  mounted within the main body  12 . The drive unit  50  contains an interior drive chamber  52  which is formed by a pair of drive halves  54  and  56 . The drive half  54  has a collar  58  and the drive half  56  has a collar  60  which both have bolt holes  62 . The collars  58  and  60  are joined together via bolts to form the drive unit  50 . 
     The drive half  54  has an inlet tube  64  which allows flow of water into the interior drive chamber  52 . An outlet tube  66  allows the water to flow out of the interior drive chamber  52  and to the sprinkler unit  30 . The inlet tube  64  has an inlet insert  68  which is connected to a hose adapter  70 . The hose adapter  70  has a washer  72  which is seated on an annular collar  74  to provide a buffer for the hose  28 . An interior surface  76  of the hose adapter  70  has female threads for coupling the hose  28  to the adapter  70 . Of course other connectors such as a snap on connector may be used. 
     The drive unit  50  has a fixed drive shaft  78 . A circular impeller  80  rotates around the fixed drive shaft  78 . The impeller  80  is in mechanical connection with the shaft  78  to cause the shaft  78  to rotate as will be described below. The impeller  80  has number of impeller blades  82  mounted to its rim. The blades  82  extend from the rim of the impeller  80  to the walls of the drive chamber  52  to maximize the force exerted from the water flowing from the inlet tube  64 . The impeller  80  is mounted on a bearing  84  which is fixed on the drive shaft  78  and allows free rotation of the impeller  80  from water pressure on the impeller blades  82  when water enters the drive chamber  52  from the inlet tube  64 . The impeller  80  has a sun gear  86  which meshes with two planet gears  88  and  90  which are mounted on two diametrically opposed shafts  92  and  94  on a carrier disk  96 . The carrier disk  96  has a center hole  98  which allows it to rotate on the shaft  78  in the drive half  54 . The drive half  54  has an interior surface  100  which has a series of longitudinal teeth  102  which mesh with the planetary gears  88  and  90 . The planet gears  88  and  90  cause a rotation reduction by being intermeshed between the longitudinal teeth  102  and the sun gear  86 , causing the carrier disk  96  to rotate. A sun gear  106  is mounted on the opposite side of the carrier disk  96  opposite the planet gears  88  and  90 . 
     The sun gear  106  meshes with two planet gears  108  and  110  which are mounted on two diametrically opposed shafts  112  and  114  on a carrier disk  116 . The carrier disk  116  has a center hole  118  which allows it to rotate on the shaft  78  in the drive half  54 . The teeth of the planet gears  108  and  110  mesh with the longitudinal teeth  102  and cause the carrier disk  116  to rotate, resulting in rotation reduction from the sun gear  106 . A sun gear  120  is mounted on the opposite side of the carrier disk  116  from the planet gears  112  and  114 . 
     The sun gear  120  meshes with two planet gears  122  and  124  which are mounted on two diametrically opposed shafts  126  and  128  on a carrier disk  130 . The carrier disk  130  has a center hole  132  which allows it to rotate on the shaft  78  in the drive half  54 . The teeth of the planet gears  122  and  124  mesh with the longitudinal teeth  102  and cause the carrier disk  130  to rotate, resulting in rotation reduction. A sun gear  134  is mounted on the opposite side of the carrier disk  130  from the planet gears  122  and  124 . 
     The sun gear  134  meshes with two planet gears  136  and  138  which are mounted on two diametrically opposed shafts  140  and  142  on a carrier disk  144 . The planet gears  136  and  138  mesh with planet gears  146  and  148  respectively which are mounted on diametrically opposed shafts  150  and  152  on the carrier disk  144 . The carrier disk  144  has a center hole  154  which allows it to rotate on the shaft  78  in the drive half  54 . The teeth of the planet gears  146  and  148  mesh with the longitudinal teeth  102  and cause the carrier disk  144  to rotate resulting in rotation reduction. A sun gear  156  is mounted on the opposite side of the carrier disk  144  from the planet gears  136 ,  139 ,  146  and  148 . 
     The sun gear  156  meshes with two planet gears  158  and  160  which are mounted on two diametrically opposed shafts  162  and  164  on a final carrier disk  166 . The teeth of the planet gears  158  and  160  mesh with the longitudinal teeth  102  and cause the final carrier disk  166  to rotate, resulting in rotation reduction. 
     The final carrier disk  166  has a collar  168  on the opposite side from the planet gears  158  and  160 . The collar  168  has a pair of slots  170  and  172  which are coupled to the drive shaft  78  via a pin  174  which is inserted through the drive shaft  78  and the slots  170  and  172 . The shaft  78  rotates with the final carrier disk  166 . The shaft  78  has a bearing  176  which is coupled to the rear wheel  14 . An O-ring  178  provides a water tight seal for the bearing  166  and another O-ring  180  provides a water tight seal for the drive chamber  52 . The combination of gearing provides gear reduction from the rotation of the impeller  80  to the rotation of the rear wheel  14 . This causes the rear wheel  14  to rotate at a 3,284 to 1 ratio to the impeller  80  in this example. Of course other reduction ratios may be achieved with different numbers of planet gears and carrier disks or different gear teeth pitch. 
     The other drive housing  56  has a closed end  182  with a shaft hole  184 . The shaft hole  184  allows the shaft  78  to be joined to the rear wheel  16  via a bearing  186  which is sealed by an O-ring  188 . The rear wheel  16  has a hub  190  to lock the rear wheel  16  on the shaft  78 . The rear wheel  16  is thus driven by the shaft  78 . 
     The front end  22  has a bumper  200 . The bumper  200  has a wide front surface  202  and a top surface  204  with a slot  206 . The slot  206  is joined to a pin  208  on the interior of the body  12 . The slot  206  and pin  208  allow the bumper  200  to slide the length of the slot  206 . The bumper  200  has a rear arm  210  which is coupled to a valve clevis  212 . The valve clevis  212  has a slot  214  which fits the rear arm  210 . A pin  216  is inserted through a mounting hole  218  to attach the valve clevis  212  to the rear arm  210 . The other end of the valve clevis  212  is installed in a cylindrical valve guide  220 . The valve guide  220  provides a hollow interior surface  222  which holds the valve clevis  212  and provides a watertight fit via an O-ring  224 . The opposite end of the valve guide  220  has an annular collar  226  which has a circular orifice  228 . A valve spool  230  has a cylindrical end installed through the circular orifice  228  and is connected to the valve clevis  212 . The opposite end of the valve spool  230  has a circular platter valve  232 . 
     The outlet  66  is coupled to an outlet adapter  234  which has a cylindrical main body  236 . The bottom of the main body  236  has a connection tube  238  which is inserted in the outlet  66 . The top of the main body  236  has an outlet tube  240  which is offset from the connection tube  238 . The outlet tube  240  has a threaded interior surface  242  and inserted in a socket  244  on the top surface  32  of the sprinkler body  10 . 
     A valve seat  250  is located in the main body  236  between the connection tube  238  and the outlet tube  240 . An O-ring  252  provides a water tight seal between the platter valve  232  and the valve seat  250 . The valve  232  and the valve spool  230  may thus be moved to cutoff water flow to the outlet tube  240 . 
     The water flow is cutoff to the sprinkler unit  10  when the bumper  200  contacts an object. This causes the bumper  200  to move backwards, which causes the arm  210  to push the valve clevis  212  through the valve guide  220  causing the valve spool  230  to push the platter valve  232  into the valve seat  250 . Water pressure from the drive chamber  50  then pushes on the opposite side of the platter valve  232  which seals the valve  232  against the valve seat  250  to insure the valve stays closed. Water flow is interrupted from the outlet tube  66  and thus water pressure will equalize stopping force on the impeller  80  thus stopping rotational movement of the wheels  14  and  16 . In order to continue operation, a user merely has to pull the bumper  200  forward removing the platter valve  232  from the valve seat  250  and water pressure resumes as water flows through the drive unit  50 . 
     The outlet tube  240  provides a socket with female threads which may be used to connect any type of irrigation head with a male connector such as the impact type sprinkler head  30 . Of course, any connectors may be used for installation of a sprinkler head. In the traveler  10  shown in FIG. 1, an impact type sprinkler head is used which sprays water in rapid bursts and may be set to rotate a fixed number of degrees. Thus, a certain non-circular pattern is irrigated which may be adjusted in terms of throw and degrees of rotation. 
     FIGS. 5A-5F are close up views of different sprinkler heads being mounted to the traveler  10 . In FIGS. 5A-5F identical elements have like element numbers to FIGS. 1-4. FIG. 5A is a close up view of a rotating sprinkler head  260  which may be mounted instead of the impact type sprinkler head. The rotating sprinkler head  260  is screwed into the threads of the socket  244 . The rotating sprinkler head  260  has a pair of arms  264  and  266  which have outlets at their ends. The water pressure from the socket  244  rotates the arms  264  and  266  as water exits the arms. 
     FIG. 5B is a close up view of another rotating sprinkler head  268  which may be mounted on the traveler  10  via the socket  244 . The rotating sprinkler head  268  has a cylindrical body  270  with an outlet  272  which throws water at a trajectory angle. Internal water driven gearing in the cylindrical body  270  permits the outlet  272  to be oscillated at different angles. For example the gearing may be set for a full 360 degrees of coverage, 180 degrees of coverage, 90 degrees of coverage etc. 
     FIG. 5C is a close up view of a triple armed rotating sprinkler head  274  mounted in the socket  244  or the traveler  10 . The sprinkler head  274  has three arms  276 ,  278  and  280  which have outlets at their ends. Water pressure through the arms  276 ,  278  and  280  will rotate the arms  276 ,  278  and  280  distributing the water at even intervals. 
     FIG. 5D is a close up view of a whirling sprinkler head  282 . The sprinkler head  282  has a water chamber  284  with a conical top  286 . The top  286  has a number of water outlets. The center of the top  286  has a propeller  288  which rotates to deflect the water from the outlets into a square pattern. 
     The types of sprinkler heads are not limited to those which rotate. Any appropriate sprinkler type which may be coupled to the socket  244  may be used. For example, in FIG. 5E, an oscillating sprinkler  290  is shown. The oscillating sprinkler  290  has an elbow connector  292  which is coupled to the socket  244 . The elbow connector  292  provides water to drive internal gearing to drive a rotating tube  294 . The tube  294  has a series of water outlets which issue forth water streams. The tube  294  rotates providing water in a desired pattern. 
     Another example is a fixed pattern sprinkler  296  shown in FIG.  5 F. The fixed pattern sprinkler  296  has a coupler  298  which is connected to the socket  244 . The fixed pattern sprinkler  296  has a number of water outlets which permit watering in a specific pattern from the body of the fixed pattern sprinkler  296 . 
     The operation of the traveling sprinkler  10  is accomplished by coupling the hose  28  to the coupler  26 . Although the sprinkler  10  generally moves forward in a line, the front wheels  18  and  20  may be rotated on the clevis  34  to move the sprinkler  10  in a circular pattern. The radius of the circular pattern depends on the angle to which the clevis  34  is rotated. The wide tracks of the rear wheels  14  and  16  in conjunction with the nubs  46  assist in providing traction on the path of the sprinkler  10 . The sprinkler  10  is placed in alignment with the area to be watered. A user may install whatever sprinkler head in the socket  244  which is desired. In certain configurations; it may be desired to use asymmetrical watering patterns such as that issued from the oscillating sprinkler  290  in FIG. 5E or the fixed pattern sprinkler in FIG.  5 F. 
     Once the water is turned on, the water is pressurized in the hose  28  and enters the drive chamber  52  of the drive unit  50 . The pressurized water comes through the inlet tube  64  and turns the impeller  80  by impacting the blades  82 . The impeller  80  turns the sun gear  86  at a high rotation rate. The series of carriers  96 ,  116 ,  130 ,  144  and  166  result in rotation reduction. The shaft  78  is coupled to the final carrier  166  and thus turns the rear wheel  14  and  16  to propel the sprinkler  10  slowly forward. The water exits the drive chamber  52  via the outlet  66 . The water is forced into the outlet adapter  234  and drives the sprinkler head  30 . The water pressure drives the sprinkler head  30  resulting in the distribution of water according to the mechanics of the sprinkler head  30 . 
     The motor drive  50  in FIGS. 1-4 may be applied to other sprinkler configurations. For example, FIGS. 6 and 7 show a modular traveling sprinkler  300 . The traveling sprinkler  300  has a rear unit  302  and a front unit  304 . The rear unit  302  has a pair of wheels  306  and  308 . The wheels  306  and  308  have a wide track area  310  with nubs  312  to assist in traction. The rear wheels  306  and  308  are coupled to a drive unit  314  which is similar to the drive unit  50  in FIGS. 1-4. The drive unit  314  has a hose coupler  316  which allows a hose to be coupled for high pressure water to be fed into the drive unit  314 . The drive unit  314  also has an outlet hose coupler  318  which allows water to flow out of the unit. A sprayer head port  320  is mounted at the top of the drive unit  314 . The sprayer head port  320  allows the mounting of any irrigation device with a common coupler as shown in FIGS. 5A-5F. In this example, the sprayer head port  320  has a plug  322  which prevents water from flowing from the sprayer head port  320 . 
     The rear unit  302  and the front unit  304  are joined by a chassis  324 . The chassis  324  has a pair of rear forks  326  and  328  which are connected to the rear unit  302 . The chassis  324  has a pair of forward forks  330  and  332  which are connected to the front unit  304 . The forks  326 ,  328 ,  330  and  332  are connected to a central pivot  334  which allows the rear unit  302  and forks  326  and  328  to pivot and the front unit  304  and forks  330  and  332  to pivot. 
     The front unit  304  is identical to the rear unit  302 . The front unit  304  has a drive unit  340  and a pair of front wheels  342  and  344 . The front wheels  342  and  344  are identical components to the rear wheels  306  and  308  and have a wide track area  346  with nubs  348  for traction. The drive unit  340  has an inlet coupler  350  which allows high pressure water to be fed into the drive unit  340 . The drive unit  340  also has an outlet hose coupler  352  which allows water to flow out of the drive unit  340 . A sprayer head port  354  is mounted at the top of the drive unit  340 . The sprayer head port  354  allows the mounting of any irrigation device with a common coupler as shown in FIGS. 5A-5F. In this example, the sprayer head port  354  has an impact sprinkler head  356 . The outlet coupler  352  allows fluid connection to another drive unit, in this example, a plug  358  is installed in the outlet coupler  352  to prevent further water flow. 
     The drive unit  340  has a hose guide  360  which is mounted to extend from the front of the front unit  304 . The hose guide  360  is attached to the drive unit  340  by screws. It is to be understood that other connection mechanisms such as bolts, welding etc. may be used. The guide may also be a set of small wheels that track a hose, a wire form which is captured by the hose, an integral extension of the motor housing, etc. or any other mechanism which may be easily placed on the hose. 
     The hose guide  360  has an arm  362  which extends laterally from the drive unit  340 . The end of the arm  362  has a semi cylindrical catcher  364  which can accommodate different diameter hoses. An umbilical hose  366  is coupled between the inlet hose coupler  350  of the drive unit  340  and the outlet coupler  318  of the drive unit  314  to provide water flow between the drive units  314  and  340 . Both the front and rear drive units  314  and  340  have an internal configuration identical to that of the drive unit  50  in FIGS. 1-4. Thus, the drive units  314  and  340  have an impeller which is propelled by pressurized water entering the drive chamber. The impeller is connected to reduction gearing to propel the wheels. As may be appreciated, since the drive units  314  and  340  are identical, they may be interchanged with each other. Additionally, any configuration of sprinkler heads may be used in conjunction with the combination of drive units and the chassis  324 . 
     In operation, the traveling sprinkler  300  is set to follow a hose  370  which is laid out in the desired watering pattern. The hose  370  has one end which is coupled to a sillcock which provides high pressure water. The hose  370  is threaded through the catcher  364  of the hose guide  360  on the front unit  304 . The other end of the hose  370  is then coupled to the hose coupler  316  of the rear unit  314 . When the water is turned on in the hose  370 , the drive units  314  and  340  propel the wheels  306 ,  308 ,  344  and  348  and move the sprinkler  300  forward. By following the hose  370 , the hose guide  360  steers the sprinkler  300  to the desired pattern in the area which should be irrigated. 
     Since the driver units are modular in nature, traveling sprinklers with additional driver units may be made. FIG. 8 shows another modular traveling sprinkler  400 . The traveling sprinkler  400  has a chassis  402  which has a hose coupler  404 . The hose coupler  404  allows connection of a hose. A pair of rear wheels  406  and  408  support the chassis  402 . The rear wheel  406  is coupled to a drive unit  410  which is similar to the drive unit  50  in FIGS. 1-4. The drive unit  410  has an inlet coupler  412  which is connected to a hose segment  414  which is connected to the hose coupler  404 . The hose segment  414  provides high pressure water to the drive unit  410 . The drive unit  410  also has an outlet hose coupler  416  which allows water to flow out of the drive unit  410  after driving the impeller (not shown). Unlike the drive unit  50  described in FIGS. 1-4, the drive unit  410  only drives the single rear wheel  406 . The opposite end of the drive unit  410  from the rear wheel  406  is enclosed. A sprayer head port  418  is mounted at the top of the drive unit  410 . The sprayer head port  410  allows the mounting of any irrigation device with a common coupler as shown in FIGS. 5A-5F. 
     Similarly, the rear wheel  408  is coupled to a drive unit  420  which is identical and interchangeable with the drive unit  410  described above. The drive unit  420  has an inlet  422  which is connected to a hose segment  424 . The hose segment  424  is connected to the hose coupler  404  and provides high pressure water to the drive unit  420 . The drive unit  420  also has an outlet hose coupler  426  which allows water to flow out of the drive unit  420  after driving the impeller (not shown). A sprayer head port  428  is mounted at the top of the drive unit  420 . The sprayer head port  428  allows the mounting of any irrigation device with a common coupler as shown in FIGS. 5A-5F. The outlet hose coupler  416  is fluidly coupled to a flexible connector  430  while the outlet hose coupler  426  is coupled to a flexible connector  432 . 
     The chassis  402  is also supported by a pair of front wheels  434  and  436 . The front wheel  434  is coupled to a drive unit  440  which is identical and interchangeable with the drive unit  410  described above. The drive unit  440  has an inlet  442  which is connected to the other end of the flexible connector  432 . The flexible connector  432  provides fluid connection from the drive unit  420  to the drive unit  440 . The drive unit  440  also has an outlet hose coupler  444  which allows water to flow out of the drive unit  440  after driving the impeller (not shown). The outlet hose coupler  444  may be used to connect other drive modules or other water driven devices. In this example, the outlet hose coupler  444  is plugged. A sprayer head port  446  is mounted at the top of the drive unit  440 . The sprayer head port  446  allows the mounting of any irrigation device with a common coupler as shown in FIGS. 5A-5F. 
     Similarly, the front wheel  436  is coupled to a drive unit  450  which is identical and interchangeable with the drive unit  410  described above. The drive unit  450  has an inlet  452  which is connected to the flexible connector  430 . The inlet  452  provides high pressure water from the drive unit  410  to the drive unit  450 . The drive unit  450  also has an outlet hose coupler  454  which allows water to flow out of the drive unit  450  after driving the impeller (not shown). In this example, the outlet hose coupler  454  is plugged. A sprayer head port  456  is mounted at the top of the drive unit  450 . The sprayer head port  456  allows the mounting of any irrigation device with a common coupler as shown in FIGS. 5A-5F. 
     In operation, a hose is coupled to the hose coupler  404 . The hose is then laid out in the desired pattern that the sprinkler  400  is desired to travel. Water is then sent into the hose. The water enters the drive units  410  and  420  and drives the rear wheels  406  and  408 . The water also continues through and enters the drive units  450  and  440  to drive the front wheels  434  and  436 . Each of the drive units  410 ,  420 ,  440  and  450  may mount sprinkler heads on their respective ports  418 ,  428 ,  448  or  458 . 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the method and system of the present invention without departing from the spirit or scope of the invention. Thus, the present invention is not limited by the foregoing descriptions but is intended to cover all modifications and variations that come within the scope of the spirit of the invention and the claims that follow.