Abstract:
A fully automated land irrigation system to irrigate regular and irregular shapes of land. The system includes an expanse of water delivery pipe moved laterally while irrigating adjacent to a stationary row of spaced access valves supplied by a water main. A swing arm is pivotally mounted to one end of the delivery pipe and a valve coupler is mounted to the opposite free swinging swing arm end. Valve connection is made and the delivery pipe irrigates while traveling to the next successive access valve. The coupler is then disconnected from the valve and the free swing arm end and coupler are ground pivoted to the next valve where connection is again made. Delivery pipe travel results in rotation of the swing arm about the valve connection. This rotation feature also enables the swing arm and the water delivery pipe to the pivoted about a valve as an anchor to a similar position on the opposite side of the water main. The invention includes a new apparatus for raising and lowering the swing arm end and coupler thus coupling and uncoupling to a valve. Also, vertical position measuring shortens the time spent coupling and uncoupling. A new coupler apparatus improves reliability and component life. A new delivery pipe navigator simplifies positioning of the delivery pipe relative to the row of access valves and provides geographic position information incorporated when selectively varying the amount of water being applied from along the delivery pipe length as the irrigator travels.

Description:
This application is a continuation-in-part of U.S. application Ser. No. 09/383,851, filed Aug. 26, 1999, now abandoned. 
    
    
     FILES OF THE INVENTION 
     The present invention pertains to a new automated approach toward forwarding a water main connection which as a result enables novel irrigation practices. 
     BACKGROUND OF THE INVENTION 
     Movable sprinklers, including a series of nozzles mounted along a delivery pipe that moves laterally along a series of access valves, have been in use for decades. One approach has the movable delivery pipe stationary while irrigating. After irrigating, the delivery pipe is disconnected from the water main and moved forward to a successive access valve and then reconnected to the water main. However, it is highly preferable to slowly forward the delivery pipe during irrigation. 
     Many ways have been suggested to manually forward the connection after intervals of forward traveling irrigation. Manually forwarding a draggable hose is today&#39;s common practice. Manual connection forwarding introduces undesirable costs, inefficiencies and operational limitations to what is otherwise the most desirable method of irrigation water application. 
     Many methods have been suggested to automate the forwarding of the supply main connection. Suggested methods found include: Engel U.S. Pat. No. 2,750,228; Hogg U.S. Pat. No. 3,281,080; Smith U.S. Pat. No. 3,381,893; Purtell U.S. Pat. No. 3,444,941; Rogers U.S. Pat. No. 3,463,175; Stafford U.S. Pat. No. 3,255,969; Nobel U.S. Pat. No. 4,295,607; and Nobel U.S. Pat. No. 4,274,584. All of these methods are very elaborate. Furthermore, all of these methods limit the delivery pipe to straight line travel only. Consequently, after completing an irrigation across a field, the delivery pipe must reverse travel the irrigated field in order to assume its original starting position. 
     U.S. Pat. No. 4,877,189 to Williams discloses a swing arm pivotably mounted to the water delivery pipe and a valve coupler mounted to the opposite free swinging swing arm end. Valve connection is made and the delivery pipe irrigates traveling the same distance found between successive access valves. The coupler is then disconnected from the valve and the free swing arm end, with coupler, is ground pivoted to the next valve where connection is again made. Delivery pipe travel results in rotation of the swing arm about the valve connection. This rotation feature also enables the swing arm and the water delivery pipe to be pivoted about a valve as an anchor to a similar position on the opposite side of the water main, representing a distinct improvement over the previous references. With Williams one length of water delivery pipe will suffice where previously two were required, greatly reducing equipment cost. Also, irrigation is circuitous and thus no backtracking is required. 
     The Williams apparatus offers many other distinct advantages over the previously mentioned references as well. Distance between valves is improved with Williams, reducing overall cost. In addition, simplified valve coupling as well as a unique approach to maintaining the delivery pipe aligned with the water main are evident. 
     The present invention serves to incorporate a number of improvements with the Williams apparatus greatly improving reliability, durability, and operating efficiency while reducing the sales price. 
     Williams incorporates a transporter for ground supporting and moving the free swinging end of the swing arm for travel between valves. It is advantageous to relocate the transporter so that during travel the access valve passes to the outside of the transporter rather than to the inside as suggested with Williams. It is also advantageous to improve the approach toward raising and lowering the transport wheels to eliminate a disruption of the ground surface as well as greatly lighten the required structure. 
     The valve coupler of Williams utilizes a set of tracks parallel to the swing arm length to allow the coupler directional alignment along the tracks during the coupling procedure as well as to facilitate straight line travel of the delivery pipe. These tracks may be improved by providing an overhang arrangement enabling much longer tracks and facilitating the aforementioned relocation of the transporter. 
     The Williams apparatus may be further improved by incorporating a sway inhibitor which provides great rigidity to the swing arm and maintains the tracks rectangularly configured relative to each other. The sway inhibitor thereby enables a greatly increased rate of transporter travel between valves. Typically, operation of the transporter requires a halt or diversion of water flow while a water supply pump remains in operation under a stressed or compromised condition. Therefore, increasing the rate of travel between valves reduces the stress or compromised condition to the pump. 
     For directional alignment perpendicular to the swing arm during valve coupling, Williams suggests moving the entirety of the swing arm apparatus via the ground surface. A further improvement is to provide an apparatus allowing coupler travel perpendicular to the swing arm length between the coupler and the tracks. Subsequently, loading on coupler and valve is greatly reduced when acting against the valve to facilitate alignment. 
     Typically all common day lateral move irrigators utilize one of three guidance systems to maintain the delivery pipe aligned with the water main. One method stretches a guide wire along the travel path. A second method buries a signal bearing guide wire along the travel path. For the third method, a small guidance ditch is dug along the travel path. The Williams apparatus offers an inherent less expensive way to maintain alignment between the delivery pipe and the water main and thus none of the above three options are required. 
     Williams suggests geographic positioning of the delivery pipe by measuring the angular alignment between the swing arm and the delivery pipe and by measuring the forward distance traveled by the delivery pipe. The appropriate position for the valve coupler along the tracks is then determined and the coupler position is then adjusted accordingly which serves to utilize the access valve as a positioning anchor. An improved approach utilizes the measured position of the coupler along the tracks and the measured forward travel direction of the delivery pipe to accurately maintain the delivery pipe a constant distance from the water main. Corrections are made by simply slightly turning the water delivery pipe toward or away from the water main as required to maintain the given distance from the main. The improved approach does not require measuring the forward distance traveled by the delivery pipe and more importantly eliminates the forces and resultant problems with utilizing the access valve as a positioning anchor. 
     U.S. Pat. No. 4,036,436 to Standal suggests adjusting the travel direction of a lateral moving water delivery pipe in accordance with the distance between a valve coupler and a delivery pipe at each successive engagement of the valve coupler to a water main access valve. Standal suggests that the water delivery pipe may be modified to travel while the coupler remains engaged to an access valve but gives no specific example of a mechanism for accomplishing this. Standal makes no reference to the more accurate navigation approach of measuring the travel direction of the delivery pipe and utilizing the measured travel direction in combination with the measured distance between valve coupler and delivery pipe to prescribe adjustments in the travel direction of the delivery pipe. 
     Williams suggests a telescoping conduit assembly to hydraulically connect the valve coupler to the swing arm. Water pressure in this arrangement will supply a large force toward extending the telescoping conduit, exerting a side force against the access valve as well as the water delivery pipe. Of further improvement, two conduit lengths pivotably connected together with one of the remaining ends pivotably connected to the valve coupler and the last end pivotably connected to the swing arm offer hydraulic connection between the coupler and the swing arm while eliminating the side force. 
     To the inventor&#39;s knowledge, no one has suggested a measuring device to determine the relative vertical position between components of the connector apparatus and an access valve. The advantages of such a device include speeding travel between valves and minimizing clearances required between the connector apparatus and an access valve. 
     Selectively varying the discharge of water along the length of a water delivery pipe has been described in U.S. Pat. No. 5,246,164 to McCann. The McCann patent discloses a system for use with center pivot irrigation in particular and suggests the approach may also be applicable to laterally traveling irrigators. McCann fails to specify a way to geographically track the position of laterally traveling irrigators other than to suggest a sprinkler line position sensor. The present invention includes novel features of the previously disclosed approach toward navigating the delivery pipe which further offer an ability to geographically track the position of a laterally traveling irrigator. 
     In summary, lateral move sprinkler mounted water delivery pipes, adapted for continuous travel during water application, offer superior and uniform application properties while irrigating rectangular areas. These qualities are most desirable. Unfortunately, no affordable and reliable method of automatically connecting the traveling delivery pipe to a stationary series of access valves has been developed for market to date, severely restricting use of these systems. 
     The present invention provides unique features to the Williams connection approach. The resultant apparatus enables affordable and reliable automated connector forwarding for continuous travel lateral move sprinklers. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred form of the invention is illustrated in the accompanying drawings in which: 
     FIG. 1 is an end elevation view of a valve coupler and swing arm apparatus of the present invention located above an access valve with pivot pad; 
     FIG. 1A is a fragmentary side elevation view of the apparatus shown in FIG. 1; 
     FIG. 2 is a view similar to the end elevation view of FIG. 1 with the valve coupler and swing arm apparatus having been lowered until a valve detector plank has made contact with the top surface of the access valve; 
     FIG. 2A is a fragmentary side elevation view of the apparatus shown in FIG. 2; 
     FIG. 3 is a view similar to the end elevation view of FIG. 2 with the valve coupler apparatus having been rolled forward until a valve catcher has contacted the access valve and consequently aligned the valve coupler with the access valve; 
     FIG. 3A is a fragmentary side elevation view of the apparatus shown in FIG. 3; 
     FIG. 4 is a view similar to the end elevation view of FIG. 3 with the valve coupler and swing arm apparatus having been lowered until ground supported by the pivot pad with the transport wheels fully raised off of the ground. 
     FIG. 4A is a fragmentary side elevation view of the apparatus shown in FIG. 4; 
     FIG. 5 is a view similar to the side elevation view of FIG. 4A with the valve coupler in a retracted position along the swing arm apparatus; 
     FIG. 6 is a fragmentary side elevation showing the entirety of a swing arm length adjuster with the valve coupler oriented similar to that shown in FIG. A. 
     FIG. 7 is an end elevation view of a valve coupler trolley assembly with a vertical position detector wheel assembly extended and the valve detector plank shown in a mostly horizontal orientation; 
     FIG. 8 is a side elevation view of the apparatus shown in FIG. 7; 
     FIG. 9 is a bottom plan view of the apparatus shown in FIGS. 7 and 8; 
     FIG. 10 is an enlarged fragmentary sectional view of a valve coupler engaged to an access valve taken on line  10 — 10  of FIG. 4A; 
     FIG. 11 is a side elevation of a swing arm apparatus of the present invention pivotably mounted at one end to a lateral move water delivery pipe with the apparatus of FIG. 6 mounted at the other swing arm end and an elevationally adjusting underboom also mounted to the lateral move water delivery pipe and extending underneath the swing arm. 
     FIG. 12 is a fragmented bottom plan view showing a sway inhibitor with portions of the remaining structure removed for clarity; 
     FIG. 13 is an enlarged fragmentary elevation view of the left end portion from FIG. 11 showing a universal pivot, a pivot angle measuring device, and features of the elevationally adjusting underboom; 
     FIG. 14 is a control diagram of various components for operation of the present system; 
     FIG. 15 is a flow chart for various components of a hydraulic system of the present invention; 
     FIGS. 16A,  16 B,  16 C and  16 D are diagrammatic top plan views of a lateral move irrigator of the present invention at various positions during forward movement; 
     FIGS. 17A,  17 B,  17 C and  17 D are top plan views of a lateral move irrigator of the present invention at various positions during rotation between two fields on opposite sides of an adjacent water main; 
     FIG. 18 is a diagrammatic illustration of a water main flow diverter utilized with the present system; 
     FIG. 19 is an enlarged fragmentary sectional view of a swing pipe pivotable connection taken on line  19 — 19  of FIG. 1; and 
     FIGS. 20A,  20 B and  20 C are diagrammatic top plan views of a lateral move irrigator of the present invention at various positions during operation of a delivery pipe navigator. 
     FIG. 21A is an end elevation of a trolley assembly with an access valve electronic detector; 
     FIG. 21B is a bottom plan view of the apparatus shown in FIG.  21 A. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention generally relates to lateral move irrigators. The present invention incorporates one or more lengths of trussed water delivery pipe  13 , mounted atop movable carts  14  forming a linear series of trussed water delivery pipes as shown in FIGS. 11,  16 A,  16 B,  16 C and  16 D. A drive  10  on each cart maintains linear alignment of the water delivery pipe  13  while powering each cart  14  to travel in a direction perpendicular to the lengths of the trussed water delivery pipe  13 . A water applicator  143  is connected along the lengths of trussed water delivery pipe  13  for selectively applying the water supplied by the trussed water delivery pipes  13  on to the field surface (shown only in FIG.  13 ). The present invention may generally include trussed water delivery pipes  13 , movable carts  14 , drive  10  and water applicator  143 . Hereafter the trussed water delivery pipes  13 , movable carts  14 , drive  10 , and water applicator  143  will be grouped together and referred to as a lateral move water delivery pipe assembly  15  as shown in FIG.  11 . 
     The present invention is intended for use in conjunction with a water main  11  as shown in FIG.  16 A. One end of the present lateral move water delivery pipe assembly  15  is to be situated adjacent the water main  11 . The water main  11  is preferably parallel to the travel direction of the water delivery pipe assembly  15 . Access valves  12  are mounted at appropriate intervals along the water main  11  enabling selective access to the water therein. 
     The present invention also involves a water delivery pipe rotator  103  in combination with a connector for joining the water delivery pipe assembly  15  to the succession of access valves  12 . 
     Water delivery pipe rotator  103  (shown in FIGS. 17A-17D) controls the drive  10  of water delivery pipe assembly  15  in order to automatically rotate the water delivery pipe assembly  15  from the typical lateral move irrigator position along one side of the water main  11  to a diametrically opposed position on the other side of water main  11 . Rotation of the water delivery pipe assembly enables automated connector forwarding and application of water along both sides of the water main  11 . 
     Water delivery pipe rotator  103  synergistically furnishes elements of a connector for connecting a series of spaced access valves  12  mounted along a water main  11  to the water delivery pipe assembly  15 . The connector  18  is an improvement that enables successive connection of the forward traveling water delivery pipe assembly  15  to the stationary series of access valves  12 . 
     The preferred present connector  18  includes a swing arm  16  as shown generally in FIG.  11 . The swing arm  16  may be a trussed span of water supply pipe  36  of a length similar to that of the trussed water delivery pipes  13  utilized as part of the water delivery pipe assembly  15 . The swing arm  16  is connected to one end of the water delivery pipe assembly  15  as shown, utilizing a pivot  17  (FIGS. 11 and 13) to allow angular movement in all directions between the swing arm  16  and the water delivery pipe assembly  15 . 
     The swing arm  16  has an outer end remote from the connection to the water delivery pipe assembly  15  with a valve coupler  19 , transporter  22  and a swing arm length adjuster  30  mounted thereon as shown in FIGS. 1-5 and specifically illustrated in FIG.  6 . The valve coupler  19  provides selective connection and disconnection along the series of access valves  12 . The swing arm length adjuster  30  is employed to enable the water delivery pipe assembly  15  to travel forward in a substantially straight line transverse to the delivery pipe length. 
     The valve coupler  19  incorporates the available weight at the swing arm outer end to influence downward travel of the outer end to forcibly align with, connect to, and forcibly open successive access valves  12 . Upward and downward travel of the valve coupler  19  is provided by an independent wheel lifter  155  as part of the transporter  22 . Hydraulic cylinders  45  pivotably mount to hydraulic cylinder mounts  70  between the upper ends of a frame crossbeam  25  and transport wheel legs  20  (FIGS.  1 - 6 ). Transport wheel legs  20  mount to frame crossbeam  25  with leg pivots  26  located therebetween. Transport wheel legs  20  are thus allowed to swing up and down (in a substantially vertical plane) so as to raise or lower each transport wheel  21  mounted to the outward swinging end of each leg  20  when hydraulic cylinders  45  are retracted or extended respectively as part of a rotation lifter  166 . The upward rotation of transport wheel legs  20  with transport wheels  21  has the effect of lowering the coupler body  24  with a plastic alignment cone  85 , to align and forcibly open an access valve  12  (access valve  12  is shown open in FIGS. 4,  4   a  and  10 ). The lowering of transport wheels  21  serves to raise the swing arm outer end and thus disconnect the valve coupler body  24  from an access valve  12 . 
     Valve coupler  19  includes a valve coupler adjuster  35  (shown generally in FIGS. 1,  2 ,  3 ,  4 , and in greater detail in FIGS. 7,  8 , and  9 ) for enabling the valve coupler body  24  to adjust position substantially in the horizontal plane and with a travel direction substantially parallel to that of the transporter  22  (the direction perpendicular to the swing arm length) to facilitate the process of aligning the coupler body  24  with an access valve  12 . A trolley frame  31  includes two rectangular tubes  32  welded on opposite sides of coupler body  24  at the middle of the tube lengths and extending horizontally to outer ends. Each set of adjacent ends of trolley frame tubes  32  are mounted to a trolley roller assembly  33  utilizing roller bearings  34  and plastic plates  47 , allowing the trolley frame horizontal linear travel in a travel direction similar to that of the transporter  22 . Compression coil springs  37  slide over the outside of each end of one of trolley tubes  32  and reside between the roller assemblies  33  and the outer ends of one of the tubes  32 . When trolley frame  31  has been acted upon by an access valve  12  to slide toward either of trolley roller assemblies  33 , the corresponding spring  37  will compress. Subsequently, the same spring  37  will extend and serve to return trolley frame  31  back to the at-rest position, centered between roller assemblies  33  when the force acting upon trolley frame  31  is released. (Trolley frame  31  is shown off-centered in FIGS. 3 and 4.) Valve coupler  19  includes a vertical position measuring device  50  as shown generally in FIGS. 1-6 and as shown in detail in FIGS. 7-9 and  14 . Vertical position measuring device  50  utilizes access valve detector plank  41  pivotably mounted to support wheel mounts  146 . Support mounts  146  are bolted to trolley frame  31 . Pivots  44  mount between detector plank  41  and support wheel mounts  146  so that detector plank  41  is allowed to rotate mostly vertically and remain rigid in the substantially horizontal plane. Detector plank  41  is thus positioned to extend outwardly and generally horizontally in the direction opposite pivot  17 . Raising the wheel legs  20  with transport wheels  21  lowers the valve coupler  19  including detector plank  41 . Detector plank  41  subsequently engages the top edge of an access valve  12  as shown in FIG.  2 A. As the valve coupler  19  is lowered the detector plank  41  is forced upward until detection by a detector plank limit switch  42  (limit switch  42  shown only diagramatically in FIG.  14 ). 
     Detector plank  41  engaging the top of an access valve  12  also serves as an access valve detector  40  as part of an access valve locator  48  as shown best in FIGS. 2 and 2 a . Access valve detector  40  serves to establish that an access valve  12  has in fact been located by an access valve locator  48  described below. 
     An access valve locator  48  as shown in FIG. 13 is utilized for positioning the detector plank  41  above an access valve  12  before the detector plank  41  is lowered onto the top of the valve. Locator  48  includes a pivot angle measuring device  165  as shown in FIG.  13  and shown diagramatically in FIG.  14 . Pivot angle measuring device  165  includes a curved rack gear  192  structurally mounted to the swing arm  16 . A pivot angle encoder  190  is mounted to the first span  13   a  of the water delivery pipe assembly  15 . A pinion gear  193  is affixed to the shaft of pivot angle encoder  190  which mates with curved rack gear  192 . Consequently, horizontal angular movement between the swing arm  16  and the first span  13   a  of the water delivery pipe assembly  15  will be measured by the angle encoder  190 . Access valve locator  48  utilizes this measurement of horizontal angular movement to determine when to halt forward travel of the connector  18  during transport between access valves  12  so as to position the detector plank  41  above an access valve  12 . 
     Hardware similar to the pivot angle measuring device  165  may be utilized to linearly align the swing arm  16  with the first span  13   a  for operation of the previously mentioned water delivery pipe rotator  103 . Hardware similar to the pivot angle measuring device  165  may also be utilized to align all of the trussed water delivery pipes  13  along water delivery pipe assembly  15 . However, alignment along the delivery pipe does not require the angle measuring capabilities preferred to measure the distance between two successive access valves  12 . Consequently, simpler hardware for measuring the alignment may be utilized as are commonplace to the industry. 
     Vertical position measuring device  50  shown in FIGS. 1-6,  7 ,  8  and  9  serves to determine the vertical position between the valve coupler  19  and an access valve  12  to facilitate alignment and coupling therebetween. Previously discussed as part or vertical position measuring device  50 , the operation of lowering detector plank  41  onto the top of access valve  12  until detection by detector limit switch  42  serves to legislate an exact vertical positioning between access valve  12  and valve coupler  19 . 
     Vertical position measuring device  50  also includes sliding tube  51  (FIGS. 7-9) mounted by a linear bearing  53 . Linear bearing  53  is mounted to a rectangular post  136 . Rectangular post  136  is mounted to one of the rectangular tubes  32  of trolley frame  31 . Linear bearing  53  enables the sliding tube  51  to travel substantially vertically while restrained from all other movements. A wheel  57  is mounted by an axle bolt  58  to the bottom of sliding tube  51  such that wheel  57  is situated to contact a concrete pivot pad  167  situated at the base of an access valve  12  as the valve coupler  19  is lowered. The sliding tube  51  is therefore forced upward relative to linear bearing  53  and thus trolley frame  31 . Wheel  57  is situated to roll along the surface of pivot pad  167  when the valve coupler  19  has been coupled to an access valve  12  and the water delivery pipe assembly  15  travels. Wheel  57  is shown in contact with a pivot pad  167  in FIGS. 4 and 4 a . A primary vertical position limit switch  59  and a secondary vertical position limit switch  60  are shown diagramatically in FIG.  14 . Limit switches  59  and  60  are positioned to detect desired positioning between sliding tube  51  and trolley frame  31  during alignment and coupling between valve coupler  19  and an access valve  12 . 
     A valve coupler aligner  100  (FIG. 10) functions as part of the valve coupler  19 . Coupler aligner  100  includes a guide  127  consisting of a plastic cone  85  attached to the bottom end of coupler body  24 . Raising the transport wheels  21  lowers the coupler mounted end of the swing arm  16  including the coupler body  24  with cone  85 . Plastic cone  85  engages the top edge of an access valve body  97 . Further lowering places weight on the valve body  97 . The engaged inclined surface of the cone  85  cams against the top lip of valve body  97  causing the cone  85  to travel horizontally to relieve the downward weight force. 
     Valve coupler aligner  100  enables cone  85  to travel in the substantially horizontal plane by utilizing available travel of the coupler body  24  along a horizontal axis substantially parallel to the length of the swing arm  16  as furnished by the swing arm length adjuster  30  (FIGS. 1A,  2 A,  3 A,  4 A,  5  and  6 ) described later. Horizontal travel of coupler body  24  substantially perpendicular to that of the swing arm length adjuster  30  is furnished to the valve coupler aligner  100  by the valve coupler adjuster  35  described earlier. Consequently, the lowering cone  85  bears against the top edge of the access valve body  97  (FIG. 10) and subsequently serves to facilitate horizontal alignment of the coupler body  24  so as to center the coupler body  24  directly over an access valve  12 . 
     When the coupler end of the swing arm is further lowered, the valve coupler  19  incorporates a coupler lock  350  as shown in FIG.  10 . The upper inner lip of plastic alignment cone  85  slides over the top edge of an access valve body  97  of access valve  12  locking the coupler body  24  from further horizontal movement. 
     When the coupler end of the swing arm is further lowered, the valve coupler  19  incorporates an actuator  29  as shown in FIG.  10 . As the coupler body  24  continues downward, the bottom edge of inner pipe  86  becomes engaged with the top surface of a plunger rod  71 . Plunger rod  71  slides linearly and vertically inside a tube bushing  73  welded to the inside of valve body  97 . Plunger rod  71  is welded to a face plate  75 . Plunger rod  71  and face plate  75  make up a poppet  72 . Poppet  72  resides in a normally closed orientation with spring  74  positioned between tube bushing  73  and a spring retainer  76  which is pinned to the upper end of plunger rod  71 . A machined face  77  of poppet  72  mates against a flat rubber gasket  78  acting to seal the closed valve from water leakage. Flat rubber gasket  78  is bolted between access valve flange  79  and riser flange  80  acting to prevent water leakage between the two flanges as well. As the coupler body  24  with inner pipe  86  is lowered, the engaged plunger rod  71  forces the poppet  72  downward, opening the access valve  12  to water flow from the water main  11 . Water pressure as well as spring  74  will cause the poppet  72  to raise and subsequently close the access valve  12  when the valve coupler  19  is raised. Seal mount  232  is bolted between the bottom face of trolley frame  31  and plastic cone  85 . Seal mount  232  holds the outer lip of a main seal  233 . The plastic cone  85  mounts against the bottom surface of seal  233 . Main seal  233  provides a rotatable, water seal between the outside surface of valve body  97  and coupler body  24 . The rotatable water seal is part of a valve coupler rotator  99  described later. 
     Swing arm  16  can include swing arm length adjuster  30  (FIGS. 1A,  2 B,  3 A,  4 A,  5 ,  6 ,  7 ,  8  and  9 ). Adjuster  30  functions to vary the distance between coupler body  24  and pipe  15  when body  24  is engaged to a valve  12  so that pipe  15  can travel in a straight line. A trolley assembly  39  includes coupler body  24  as part of trolley frame  31  which is mounted by trolley roller assemblies  33 . Roller assemblies  33  engage rails  91  to carry trolley assembly  39  between an inner end closest to pivot  17  and an outermost end away from the pivot  17 . Roller assemblies  33  utilize nylon rollers  92  formed of nylon or another appropriate low friction noncorrosive material which serve to support and move the bottom surface of rails  91 . The rails move along the top of the nylon rollers  92  when a ground support  120 , described later, has engaged a pivot pad  167 . Pallet rollers  93  are also provided and offer support and travel along the top of the rails  91  for the trolley assembly  39  when ground support  120  is not in contact with pivot pad  167 . Four cam followers  102  are mounted to each roller assembly  33  so as to roll along the inside and outside lower edges of rails  91  to maintain each roller assembly  33  in alignment with the corresponding rail  91 . 
     A trolley drive  84  as part of swing arm length adjuster  30  (FIG. 7) propels the trolley assembly  39  along rails  91 . Trolley drive  84  includes a roller assembly  33   a . Roller assembly  33   a  has a self aligning flange mount bearing block  94   a . A driveline  95  extends through bearing block  94   a  with a nut  96  threaded onto one end of driveline  95 . A splined axle  98  extends through two bearing blocks  94  of roller assembly  33  with a splined stub end  129  protruding from an end of the driveline  95  toward roller assembly  33   a . Splined stub end  129  is mounted by ball spline coupler  151  such that the ball spline coupler  151  freely travels along the length of splined stub end  129  while being rigid to rotation about the axis of the axles between them. The end of ball spline coupler  151  facing roller assembly  33   a  is welded to the remaining end of driveline  95 . Consequently driveline  95  and splined axle  98  are locked so as to rotate together but are extendible along the axis of rotation. 
     One sprocket  107  is mounted to driveline  95  and another to splined axle  98 . Two idler sprockets  106 FIG. 8) are mounted to each roller assembly  33  in alignment with each sprocket  107  so that a roller chain  108  may wrap under the idlers  106  and over a sprocket  107  (best shown in FIG. 8) and extend end to end along side each rail  91 . Each sprocket  107 , idler sprockets  106  and roller chain  108  are oriented to enable both roller assemblies  33  to be driven simultaneously via driveline  95  and splined axle  98 . The sprockets and chain maintain the trolley assembly  39  perpendicularly aligned with the rails  91 . To the inside of one of the sprockets  107 , driven sprocket  109  mounts to splined axle  98  (best shown in FIG.  7 ). A drive motor  111  mounts to a pivoting mount with a drive sprocket mounted to the drive shaft of drive motor  111 . A drive chain  114  extends over the drive sprocket and driven sprocket  109  and is linked back to itself to form a closed loop to be tensioned by adjustment of the pivoting mount. When drive motor  111  is operated, splined axle  98  and driveline  95  rotate forcing sprockets  107  against the linearly stationary roller chain  108 , forcing the roller assemblies  33  in the desired direction along the rails  91 . 
     An indexing sprocket  116  mounts to the inside of sprocket  107  on driveline  95  (FIG.  7 ). A trolley encoder  115  (FIG. 8) mounts to a spring tensioned pivoting mount  117  located on the roller assembly  33   a . Indexer sprocket  119  mounts to the input shaft of encoder  115 . An indexer roller chain  118  extends over sprockets  116  and  119  and connects back to itself Spring tensioned pivot mount  117  appropriately tensions trolley indexer roller chain  118 . Trolley encoder  115  will measure any movement of driveline  95  and thus roller assemblies  33  and ultimately trolley assembly  39  along the length of rails  91  as part of a swing arm length measuring device  208  (FIG.  14 ). The previously discussed pivot mount associated with drive motor  111  (not well shown) is similar to tensioned pivot mount  117  except the spring and nut arrangement of spring tensioned pivot mount  117  is replaced with a nut on each side of the plate to lock the pivot mount in place as required to accommodate the torque of drive motor  111 . 
     The reason that trolley drive  84  is mounted on the trolley assembly  39  is so that when the swing arm length adjuster  30  functions to enable straight line travel of the water delivery pipe  15 , the drive components of trolley drive  84  remain oriented above the pivot pad  167  and consequently remote from potential entanglement with adjacent crops. 
     An access valve catcher  135  may be facilitated by the aforementioned swing arm length adjuster  30  as well as the aforementioned valve coupler adjuster  35 . The access valve catcher  135  serves as part of the valve coupler  19  as shown best in FIGS. 7-10. 
     Three rectangular posts  136  are welded to trolley frame  31  and extend downward therefrom to a height slightly above the ground engaging elevation of ground support wheels  27 . A “v”-configured catcher  137  (FIG. 9) is welded to the bottom of posts  136  in a mostly horizontal orientation with the mouth of catcher  137  facing the outer end of the swing arm  16  and thus away from pivot  17 . Upon appropriate positioning of the valve coupler  19  relative to an access valve  12  by the access valve detector  40  as shown in FIGS. 2 and 2 a , the trolley assembly  39  of the swing arm length adjuster  30  may be powered to move outward, away from the pivot  17 . Consequently, “v”-configured catcher  137  travels until engaging an access valve  12  when one of two catcher plastic wear surfaces  138  mates against access valve body  97 . A catcher plastic  138  is affixed along each of the two arms of the “v”-configured catcher  137  to minimize friction and wear between the “v”-configured catcher  137  and the valve body  97  of an access valve  12 . The powered trolley assembly  39  forces the catcher plastic  138  against the side surface of access valve body  97 , acting to move the catcher  137  in a direction perpendicular to the length of the swing arm length adjuster  30 . Travel is provided by the valve coupler adjuster  35  until both catcher plastics  138  are in contact with access valve body  97  as shown in FIGS. 3 and 3A. Consequently, travel along the swing arm length adjuster  30  as well as along the valve coupler adjuster  35  halts. With both catcher plastics  138  engaging valve body  97 , the valve catcher  135  has positioned itself to access valve  12  in two dimensions and consequently has aligned access valve  12  to the aforementioned guide  127  of valve coupler aligner  100 . 
     Just prior to the engagement of the second catcher plastic  138  to access valve body  97 , a catcher limit switch  140  (shown diagramatically in FIG. 14) engages access valve body  97  and subsequently is actuated. The limit switch  140  acts to indicate completion of the alignment of plastic cone  85  with access valve body  97 . Consequently, horizontal position measuring device  145  has functioned to determine that the desired orientation between valve  12  and aligner  100  has been achieved. 
     It is advantageous to utilize valve catcher  135  in combination with valve coupler aligner  100  to align an access valve  12  to valve coupler body  24 . Because of terrain variations in the ground support of cart  14   a  and the ground support of transport wheels  21 , a small misalignment (a few inches or more) can result when aligning an access valve  12  to coupler body  24  utilizing the valve catcher  135 . Therefore a “fine” secondary alignment is required as provided by valve coupler aligner  100 . Conversely, utilizing the valve coupler aligner  100  by itself to align an access valve  12  to valve coupler body  24  would require an alignment cone  85  in the realm of thirty inches in thickness (rather than four inches in thickness) in order to provide the range of alignment available with the valve catcher  135 . Thirty inches in thickness would also require twenty-six additional inches of clearance between the coupler body  24  and an access valve  12 . Utilizing the valve coupler aligner  100  by itself would also require additional hardware to align the alignment cone  85  to an access valve  12  along the travel axis of the swing arm length adjuster  30 . 
     To the inside of roller assemblies  33 , bolted to rectangular tubes  32  of trolley assembly  39  are support wheel mounts  146  which extend downward and furnish an axle extending horizontally so that a support wheel  27  may mount on each side of the downward extension as shown in FIGS. 7-9. Support wheel mounts  146 , support wheels  27 , and trolley frame  31  serve as a ground support  128  for the coupler mounted end of the swing arm  16  when the transport wheels  21  have been raised in order to connect valve coupler body  24  to an access valve  12 . When the coupler body  24  is connected to an access valve  12 , the support wheels  27  are subsequently anchored from all ground movement except rotation about the access valve  12  as utilized by a valve coupler rotator connection  99  described later. With support wheels  27  anchored from travel, rails  91  travel anchored radially with respect to access valve  12  when the swing arm length adjuster  30  operates. 
     A valve coupler rotator connection  99 , shown best in FIGS. 4 a ,  5  and  10 , includes the aforementioned support wheels  27 . Support wheels  27  are rotatable about a common axis with the coupler body  24  located between support wheels  27  along the axis. Such alignment provides pivotable ground support for the swing arm  16  at the coupler mounted end of the swing arm  16  so the swing arm  16  is freely rotatable about connection to an access valve  12  regardless of the longitudinal position of the previously described swing arm length adjuster  30  as indicated by the extreme positions shown in FIGS. 4A and 5. The aforementioned valve actuator  29  (FIG. 10) has features that allow rotation between the coupler body  24  and a stationary access valve  12  when the coupler body  24  is connected to the access valve  12 . Consequently, the swing arm  16  may rotate when the valve coupler  19  is connected to a stationary access valve  12 . 
     In a fully lowered position, as shown in FIGS. 1 and 1A, the previously mentioned transport wheels  21  may be rolled along the ground surface as part of a transporter  22  for transporting the swing arm outer end with the valve coupler  19  and swing arm length adjuster  30  mounted thereon between successively connectable access valves  12  as indicated by curved arrow  87  shown in FIG.  16 D. Transporter  22  includes two hydraulic wheel motors  88  each mounted to the free end of transport wheel legs  20  as shown in FIG. 1A. A wheel hub  89  mounts the output shaft of each wheel motor  88  with a transport wheel  21  bolted to each wheel hub  89  as shown in FIG.  1 . Hydraulic wheel motors  88  are plumbed in parallel. When no oil is flowing to motors  88  from a pressure device  169 , parallel plumbing  245  as shown in FIG. 15 enables oil to flow between the two motors  88  such that the motors are free to simultaneously rotate in opposite directions. Consequently, the coupler mounted end of the swing arm may remain stationary as the transport wheels  21  rotate slightly in opposite directions to compensate for the varying distance between them generated when transport wheels  21  are raised or lowered in contact with the ground surface. 
     A rail truss  125  may be incorporated to structurally tie rails  91  of the swing arm length adjuster  30  to each other and with the supply pipe  36  of the swing arm  16  as shown in FIGS. 1-6. Each rail  91  may be supported toward the center of its length by a frame crossbeam  25  bolted along the outside face of each rail  91  and extend outward to support leg pivots  26 . Frame crossbeam  25  extends upward from leg pivots  26  to support hydraulic cylinder mounts  70   a . Crossbeam  25  also extends perpendicular to and across rails  91 , tying together the cylinder mounts  70   a  and also the rails  91 . An upper strut  121  is bolted to crossbeam  25  near each of the two cylinder mounts  70   a . Each upper strut  121  extends upward and inward and bolts to the supply pipe  36  as best shown in FIG. 5. A lower strut  52  is bolted to frame crossbeam  25  near each leg mount  26 . Each lower strut  52  extends upward and inward and bolts to the supply pipe  36 . A basebeam  123  extends perpendicular to the length of rails  91  and is bolted to the ends of rails  91  tying them together. Basebeam  123  extends outward beyond the ends of rails  91  to a length similar to the length between leg mounts  26 . Struts  239  (shown in FIGS. 6 and 12) extend between the ends of basebeam  123  and supply pipe  36 . Struts  139  tie in to supply pipe  36  adjacent to the tie-in of Struts  52  and struts  121 . A compression truss  249 , shown in FIGS. 6 and 12, extends between the ends of basebeam  123  upward and ties in to a support truss  104   a  of swing arm supply pipe  36 . 
     A rail overhang  275  serves as part of the swing arm length adjuster  30  to extend the length of the swing arm length adjuster  30  as shown in FIGS. 1A and 2A. Crossbeam  25  is configured to allow the trolley  39  as well as a portion of swing pipe  110  to pass underneath and outward beyond crossbeam  25  to a remote outer end of rails  91 . Rails  91  are thus extended well beyond crossbeam  25 . Consequently, the apparatus weight may be concentrated toward the inward end of the rails  91 , reducing the cantilevered weight force when the trolley  39  is toward the inner ends of rails  91 , as shown in FIG. 5, and the entire apparatus is ground supported by support wheels  27  as shown. (Rails  91 , crossbeam  25  and legs  20  are constructed out of aluminum to further reduce the cantilevered weight force.) In addition to enabling the trolley  39  to travel outward of crossbeam  25 , the rail overhang  275  including crossbeam  25  supports the transporter  22  which enables access valves  12  to pass between the transporter  22  and the outer end of the swing arm length adjuster  30  during operation of the transporter  22  for carrying the valve coupler  19  between access valves  12 . (Crossbeam  25  functions as part of rail overhang  275  as well as part of rail truss  125 .) Crossbeam  25  is supported by strut  121  and strut  52  to maintain the crossbeam  25  rigid despite rotation forces introduced by the configuration of transport wheels  21  and wheel legs  20 . 
     A sway inhibitor  130  can be part of swing arm length adjuster  30  and can be part of swing arm  16 . Inhibitor  130  affixes to rail truss  125  and rail overhang  275  (FIG.  12 ). Inhibitor  130  helps provide rigidity to adjuster  30  in a substantially horizontal plane, thus helping maintain rails  91  configured rectangularly relative to each other. Basebeam  123  is bolted along the inner ends of rails  91  and extends outward beyond each rail end to a length similar to that found between the leg pivots  26 . Sway struts  126  are bolted between crossbeam  25  near leg pivots  26  and the ends of basebeam  123 . Other sway struts  251  extend between crossbeam  25  near leg pivots  26  and the basebeam ends of rails  91 . End sway struts  266  extend between crossbeam  25  near leg pivots  26  and end beam  196 . End beam  196  extends between the outer ends of rails  91 . 
     A swing pipe  110  can be utilized to operably flow water between coupler body  24  and supply pipe  36  (FIGS.  1 - 6 ). Swing pipe  110 , which can be part of adjuster  30 , acts as a pivotable link between coupler body  24  linearly traveling along the length of adjuster  30  and supply pipe  36 , pipe  36  stationary relative to the travel of coupler body  24 . Swing pipe  110  includes S-link pipe  131  which consists of a length of water conduit with a female coupling  132  fitted to one end to be secured to a male coupling  133   a  (inside of female coupling  132 ) fitted to supply pipe end box  134  with supply pipe end box  134  welded to the outer end of supply pipe  36 . The remaining end of S-link pipe  131  is fitted with a male coupling  133  secured and inside of a female coupling  132  fitted to one end of a C-link pipe  139 . C-link pipe  139  consists of a length of water conduit with female couplings  132  fitted to both ends. The end of C-link pipe  139  opposite to the end secured to S-link pipe  131  is secured to a male coupling  133   b  fitted to the side of coupler body  24 , positioned horizontally and protruding in the same direction as male coupling  133   a . 
     All three male couplings  133  are basically identical consisting of a short length of pipe  141  with a ring  142  welded along the pipe length as shown in FIG.  19 . All three female couplings  132  are identical, consisting of a pipe length  144  roughly as long as pipe  141 . A ring  246  is welded to the outer end of pipe  144 . Ring  246  has an internal diameter smaller than the internal diameter of the pipe  144  and also smaller than the external diameter of ring  142 . A pipe  247  is welded to the outside diameter of ring  246 . Pipe  247  has an internal diameter slightly larger than the external diameter of ring  142  so that ring  142  may be fitted inside pipe  247 . A flange  147  with an internal dimension slightly larger than the diameter of pipe length  247  is welded to the outer end of pipe length  247 . A two piece retaining ring  163  bolts to flange  147  for securing ring  142  in the cavity formed between retainer  163  and ring  246 . A swing pipe seal  149  is fitted in the cavity and butts up against ring  246 . A washer bearing  161  of nylon or another appropriate material resides between the face of seal  149  opposite ring  246  and a face of ring  142 . A two piece washer bearing  162  also of nylon or another appropriate washer/bearing material resides between the other face of ring  142  and the face of retaining ring  163 . Retaining ring  163  bolts to flange  147  securing female couplings  132  with male couplings  133 . Washer bearings  161  and two piece washer bearings  162  offer a bearing surface for rotation between male coupling  133  and female coupling  132 . Two piece washer bearing  162  also serves to accommodate water pressure in the swing pipe  110  which acts to expand the secured couplings and thus forces the face of ring  142  and the face of two piece retaining ring  163  against two piece washer ring  162 . Additionally, paired couplings require a degree of travel perpendicular to their axis of rotation to allow full travel of the valve coupler adjuster  35 . Washer bearings  161  and  162  are adequately sized to permit a limited degree of travel between male couplings  133  and female couplings  132  as required for operation of the valve coupler adjuster  35 . 
     Swing pipe  110  is configured so that S-link pipe  131  and C-link pipe  139  reside predominantly toward the pivot  17  and travel in a substantially vertical plane during utilization of the swing arm length adjuster  30 . Swing pipe  110  could also be configured so that S-link pipe  131  and C-link pipe  139  reside predominately away from pivot  17 . C-link pipe  139  would then be positioned mostly horizontal and S-link pipe  131  would be positioned mostly vertical when coupler  24  is oriented along the swing arm length adjuster  30  as shown in FIG.  5 . (This configuration would require modification of the structure supporting transport wheels  21  corresponding with modification required to crossbeam  25 .) Configuring swing pipe  110  toward pivot  17  reduces the cantilevered weight force on various structural members resulting from the weight (including water) of swing pipe  110  when positioned toward the inner end of the swing arm length adjuster  30  as shown in FIG.  5 . Swing pipe  110  could also be configured to travel in a substantially horizontal plane requiring structural modification to the swing arm length adjuster  30 . 
     The pivot  17  as shown in FIGS. 11,  13 ,  16 AA,  16 B,  16 C and  16 D, and as shown best in FIG. 13 includes a universal pivot  154   a  mounted between the swing arm supply pipe  36  of swing arm  16  and a first delivery pipe span  13   a  of the water delivery pipe assembly  15 . Universal pivot  154   a  incorporates a ball  164  attached to supply pipe  36  and seated in a ball socket  159 . Ball socket  159  is mounted to first delivery pipe span  13   a . Universal pivot  154   a  allows vertical angular movement between the swing arm supply pipe  36  and the first delivery pipe span  13   a  of the water delivery pipe assembly  15  as required to accommodate elevational variation in the terrain. Universal pivot  154   a  also allows horizontal angular movement between the trussed water supply pipe  36  and the first delivery pipe span  13   a . Horizontal angular movement is required when the transporter  22  is utilized to transport the valve coupler  19  between access valves  12  and also as required when the water delivery pipe assembly  15  travels straight forward with the coupler body  24  connected to an access valve  12 . Horizontal angular movement is further required to maintain the supply pipe  36  and first span  13   a  directionally aligned during operation of the delivery pipe rotator  103 . 
     Lateral move water delivery pipe assembly  15  requires movable carts  14  mounted at both ends of one trussed delivery pipe  13  along water delivery pipe assembly  15  so that both ends of all delivery pipes will by [be?] movably ground supported. Middle delivery pipe span  13   c  serves this purpose as shown in FIG.  11 . Middle delivery pipe span  13   c  is similar to delivery pipes  13  of water delivery pipe assembly  15  except that movable carts  14   c  and  14   d  are mounted at ends of pipe span  13   c  instead of just one end as is common to the remaining delivery pipes  13  along water delivery pipe assembly  15 . 
     Water delivery pipes  217  and swing arm supply pipe  36  utilize truss rods  229  (FIGS. 6,  11 ,  12  and  13 ) stretched along the bottom of a series of support trusses  104  for the purpose of elevationally supporting each of the pipes  217  and  36  by tensioning truss rods  229  so as to constitute a trussed pipe span. Compression truss  249  ties into the swing arm  16  along the bottom of a support truss  104   a  and extends downward and outward with the other end of truss  249  mounted to the ends of basebeam  123 . When the coupler body  24  approaches the position as shown in FIG. 5, significant weight from the transporter  22 , swing arm length adjuster  30  and valve coupler  19  is cantilevered outward of the ground support of support wheels  27 . Compression truss  249  serves to support the counterbalance of said cantilevered weight with the weight of the swing arm  16 , subsequently placing compression truss  249  in a compression force. 
     Also a component of the aforementioned sway inhibitor  130 , compression truss  249  incorporates cross members  252  (FIG. 12) to establish great strength in that plane to prevent sway between the basebeam  123 , and thus the rail truss  125 , and the swing arm  16 . In addition, cross struts  153  (FIG. 12) are bolted between support trusses  104  (FIGS. 12 and 13) of the swing arm supply pipe  36  to further eliminate sway in the swing arm  16  and subsequently the rail truss  125 . 
     An elevationally adjusting underboom  255  as shown in FIG. 13 serves to provide precision water application for most crop heights to the cropland underneath the swing arm  16 . Adjusting underboom  255  includes an underboom  260 . Underboom  260  includes an underboom supply pipe  256 . Supply pipe  256  is supported along its length by a support truss  257  offering elevational rigidity to the supply pipe  256 . 
     Elevationally adjusting underboom  255  also includes an elevation adjuster  265 . Elevation adjuster  265  includes pivots  253  located between support truss  257  and the first cart  14   a  of water delivery pipe assembly  15 . Pivots  253  enable underboom  260  to be pivoted up or down consequently raising or lowering the end of underboom  260  remote from pivots  253 . A cable  254  is attached along supply pipe  256  and extends around a pulley  258  mounted to cart  14   a  and attaches to swing arm supply pipe  36 . The, elevation adjuster  265  provides to maintain the supply pipe  256  a similar distance below swing arm supply pipe  36  regardless of varying elevation at the coupler mounted end of the swing arm, at cart  14   a  or at cart  14   b . Maintaining supply pipe  256  elevationally close to supply pipe  36  enables consistent and thus much greater ground clearance. 
     The connector  18  and subsequently the water delivery pipe assembly utilize a control system  150  to actualize operation of the present system. The various electrical components and the relationship between them are illustrated in the control diagram as shown in FIG.  14 . Hydraulic components and the relationship between them are illustrated in the flow chart as shown in FIG.  15 . 
     Control system  150  includes programmable logic controller  160  hereafter referred to as plc  160 . Plc  160  may be comprised of commercially available components arranged to interpret signal impulses and, according to the appropriate programmed response, initiate or stop operation of various electrically controlled components over selected time periods. Plc  160  includes logic  170  as the means to store the programmed information utilized for providing automated and sequential operation. Logic  170  is a commercially available component. 
     A power source provides the electricity to power the drive  10  of the water delivery pipe assembly  15  and the control components shown in FIG.  14 . The power source may include a diesel generator  243  mounted to one of the movable carts  14   a  (FIG.  13 ). Alternately, electricity may be produced by a generator driven by a water powered motor. The water motor would be hydraulically connected to the water delivery pipe assembly  15  or the connector  18 . 
     Describing operation of the present invention may best begin when the water delivery pipe assembly  15  and connector  18  are positioned as shown in FIG.  16 A. (The dashed lines in FIGS. 16A-16D and  17 A- 17 D illustrate previous positions of the connector  18  and the water delivery pipe assembly  15  where operational changes occur and also illustrate the paths traveled by the movable carts  14  preceding the present position shown.) The water delivery pipe assembly  15  has previously been applying water while traveling forward along the water main  11  and is now situated somewhere between ends of the field being irrigated. As shown in FIG. 16, valve coupler  19  has just been forwarded from a previous connection to an access valve  12  and has now been again connected along the series of access valves  12  to access valve  12   a.    
     The valve coupler  19 , when connected to access valve  12   a , has subsequently opened the access valve  12   a  allowing the pressurized water in water main  11  to flow into and through the connector  18 , through water delivery pipe assembly  15  and finally on to the ground surface. Subsequent to valve opening, the transport wheels  21  are further raised, now off of the ground, until triggering the leg up limit switch  205 , having assumed a position similar to that shown in FIGS. 4,  4   a  and  5 . In accordance with the triggering of leg up limit switch  205 , plc  160  begins operation of drive motors  152  and  157  in response to input pulses from percentage timer  156 . 
     Percentage timer  156  is a commercially available and conventionally employed component providing manually adjustable control for selectively prescribing the amount of water applied when the water delivery pipe assembly  15  traverses and subsequently irrigates a field. Percentage timer  156  accomplishes this by dictating the rate of simultaneous forward travel at movable carts  14   a  and  14   e . Movable carts  14   a  and  14   e  are powered by drive motors  152  and  157 , respectively. Drive motors  152  and  157  typically have only one forward speed. Consequently, percentage timer  156  dictates the rate of forward travel by regulating the percentage of time drive motors  152  and  157  operate. For example, percentage timer  156  might be manually set to power the motors  152  and  157  for ten seconds and then discontinue power for twenty seconds. Maximum operation time of drive motors  152  and  157  results in a minimum amount of water applied. More water is applied when the drive motors  152  and  157  are operated less percentage of the time. 
     When movable carts  14   a  and  14   e  (FIGS. 11 and 16A) simultaneously travel forward, the angular alignment between the first span  13   a  and the second span  13   b  as well as the angular alignment between span  13   c  and last span  13   d  along water delivery pipe assembly  15  will be altered because movable carts  14   b  and  14   d  remain stationary. The altered alignment is detected by means typical to the industry which operates the drive motors  158  of drive  10  to forwardly move the movable carts  14   b  and  14   d . Movable carts  14   b  and  14   d  travel forward until first span  13   a  and second span  13   b  as well as span  13   c  and span  13   d  are once again in linear alignment at which points the drive motors  158  are independently switched off. The same means of control is employed for maintaining linear alignment along the lengths of trussed water delivery pipe  13  of the water delivery pipe assembly  15 . Consequently, simultaneous forward travel of movable carts  14   a  and  14   e  initiates subsequent similar forward travel of all remaining movable carts  14  of the water delivery pipe assembly  15  and is commonplace to the industry. 
     As water delivery pipe assembly  15  travels, a guidance system is required to maintain delivery pipe assembly  15  at a constant distance from water main  11 . At least three guidance systems are commercially available and commonplace to the industry at present. However, the unique operation of connector  18  of the present invention provides a novel and far less expensive way to maintain the water delivery pipe assembly  15  traveling in a path that is substantially parallel to water main  11 . 
     Delivery pipe navigator  210  (FIG. 14) includes a straight line determiner  295 . Straight line determiner  295  utilizes plc  160  to interpret information from the swing arm length measuring device  208  and consequently from trolley encoder  115  to determine the distance between a point on water delivery pipe  15  and water main  11 . Utilizing plc  160 , navigator  210  compares the distance determined by straight line determiner  295  with a given preferred distance between the point and the water main. Navigator  210  then initiates small adjustments in the travel direction of delivery pipe  15  to keep the path of the delivery pipe  15  substantially parallel to the water main  11 . 
     If the information from straight line determiner  295  indicates that delivery pipe  15  has moved too close or too far away from water main  11 , navigator  210  will act by halting operation of drive motor  157  of movable cart  14   e  or drive motor  152  of movable cart  14   a  (FIG.  11 ). Operation of drive motor  152  or drive motor  157  is halted for a determined length of time with said time elapsing only while drive motor  157  or drive motor  152  is actually under power as dictated by plc  160  in accordance with the input from percentage timer  156  as previously discussed. (Straight line determiner  295  can also provide the same function by determining a distance between a point on delivery pipe  15  and an axis running parallel to the water main  11 . Navigator  210  then compares the determined distance with a given preferred distance between the point and axis and, accordingly, adjusts the travel direction of delivery pipe  15 . As an example, determiner  295  can determine the distance between a point on delivery pipe  15  and a laser beam, the laser beam running parallel to water main  11 . The laser beam is situated to run transverse to the delivery pipe  15  such that sensors are mounted on the delivery pipe  15  and detect the laser beam when delivery pipe  15  is off-course. Navigator  210  then implements a course correction.) Delivery pipe navigator  210  can utilize plc  160  to interpret information from the swing arm length measuring device  208  in order to function as a travel direction determiner  270 . Travel direction determiner  270  serves to determine the travel direction of delivery pipe  15 . By utilizing the travel direction of delivery pipe  15  in combination with the distance determined by straight line determiner  295 , navigator  210  can calculate and implement much more accurate adjustments to the travel direction of delivery pipe  15  compared with utilizing the distance determined by straight line dterminer  295  only. 
     As an example, navigator  210  is configured to utilize straight line determiner  295  and travel direction determiner  270 . Upon coupler  19  first being connected to an access valve  12  (FIG.  16 A), determiner  295  is utilized. The position measurement of coupler body  24  along rails  91  is read from trolley encoder  115  by plc  160  which then multiplies the measurement by a constant to obtain the component of the measurement substantially representative of a distance perpendicular from the water main  11  to the delivery pipe  15 . (The delivery pipe is approximated to be positioned exactly half way between access valves and, therefore, a constant is employed). 
     Next navigator  210  utilizes travel direction determiner  270 . Determiner  270  compares the present distance between the delivery pipe  15  and water main  11  and a previous determined distance between delivery pipe  15  and water main  11 , the previous distance as measured by straight line determiner  295  when the delivery pipe  15  was previously positioned as shown in FIG.  16 B. (Determiner  295  attains the previous determined distance by simply reading the trolley encoder  115 . Because the swing arm  16  is substantially perpendicular to the water main  11 , no multiplication by a constant is necessary.) The distance traveled by delivery pipe  15  between each position where a measurement is made by straight line, determiner  295  is approximated to be identical (approximately  51  feet of delivery pipe travel). Therefore, travel direction determiner  270  simply compares the present distance measured with the previous distance measured and derives a slope representative of the direction of the path the delivery pipe has traveled. 
     Lastly, navigator  210  compares the present distance measured by straight line determiner  295  with a given preferred distance between delivery pipe  15  and water main  11  and in doing so derives a preferred slope. Navigator  210  subtracts the preferred slope from the present slope to determine the change in travel direction required of delivery pipe  15 . Navigator  210  then implements that change in travel direction. 
     The above example of navigator  210  incorporates the two discussed approximations to greatly simplify calculations and to more easily illustrate the workings of navigator  210 . The disclosure below illustrates a like example of navigator  210  absent the two approximations. (The improvement in accurately guiding delivery pipe  15  through exact calculation versus employing the two approximations is mostly negligable.) 
     After making connection to the next forward access valve  12  as shown in FIG. 16A, plc  160  receives the position of trolley assembly  39  along rails  91  read from trolley encoder  115 . Plc  160  then utilizes the reading from encoder  115  to calculate the relative geographic position of water delivery pipe assembly  15  or more specifically geographic coordinates for cart  14   a . According to the geometric axiom, if the lengths of the three sides of a triangle and the coordinates of two of the comers are known, the third corner&#39;s coordinates can be determined. As shown in FIG. 20A, given the fixed locations of access valves  12   q  and  12   r , the “Distance E” between the two access valves is known. The “Distance F” between access valve  12   q  and cart  14   a  is known because forward travel of cart  14   a  has been halted at a specified point in the extension of swing arm length adjuster  30 . The present reading from encoder  115  translates a distance measurement “Distance G” between access valve  12   r  and cart  14   a . Thus the length of all three sides of the triangle are known. Because access valves  12   q  and  12   r  are fixed, they may be assigned coordinates in an X-Y coordinate system and thus the coordinates of two of the three corners of the triangle are known. Therefore, plc  160  calculates the coordinates of the third comer of the triangle and thus the present coordinates of cart  14   a  (s,p). (Coordinate “p” represents the perpendicular distance from water main  11 ) 
     By establishing the exact coordinates of cart  14   a , plc  160  may then subtract from these coordinates (s,p) a set of coordinates (f,g) which represent the position of cart  14   a  at the preceding geographic position where coordinates were derived and a travel direction adjustment may have been required. As shown in FIG. 20C, plc  160  subtracts from the coordinates of cart  14   a  (s,p) the coordinates (f,g) coordinates of cart  14   a  at the preceding geographic position where coordinates were derived. The difference between (f,g) and (s,p) represents the slope of a line D and thus the “Present Travel Direction” of the delivery pipe assembly  15 . (The slope of a line is defined as the change in the Y coordinate divided by the change in the X coordinate.) At this time, plc  160  also subtracts the present coordinates (s,p) from preferred coordinates (j,k) that represent the optimum positioning of cart  14   a  (on the “Preferred Travel Path”) for the next future position of cart  14   a  where coordinates would be derived and an adjustment in the travel direction may be required. The difference between coordinates (s,p) and (j,k) represents the slope of a line E and thus the “Preferred Travel Direction” of the delivery pipe assembly  15  in order to attain the preferred future positioning of cart  14   a  at coordinates (j,k) along the “Preferred Travel Path.” Plc  160  then subtracts the “Present Travel Direction” (slope of line D) from the “preferred Travel Direction” (slope of line E) to obtain the change in travel direction (slope) required which could also be described as a “Course Correction.” 
     Plc  160  then multiplies the “Course Correction” by a constant number to obtain a “Course Correction in Seconds of Operation.” Plc  160  subsequently implements the appropriate “Course Correction in Seconds of Operation” to the delivery pipe assembly  15  to align the water delivery pipe assembly  15  to the “Preferred Travel Direction.” Plc  160  adjusts the travel direction of water delivery pipe assembly  15  by halting operation of one of the drive motors  152  or  157  as previously discussed in the aforementioned procedure for making said adjustments. Whether the “Course Correction” is a positive or negative number will determine which of the operating drive motors  152  and  157  will be halted. 
     Utilizing an X-Y coordinate system and calculating the difference between line slopes is a precise way of incorporating straight line determiner  295  and travel direction determiner  270  to calculate course corrections. (For travel direction adjustments at the onset of an irrigation cycle, perhaps at a field end as shown in FIGS. 17A-17D, where no preceding distance from the water main coordinates are available, plc  160  makes travel direction adjustments according to only the “p” coordinate (distance from water main  11 ), as previously discussed, with somewhat less accurate results. 
     If the preceding course correction was implemented by halting operation of the outermost cart (while cart  14   a  remains in operation), a small compensation may be implemented to retain maximum precision when calculating the “Present Travel Direction.” When course corrections involve halting the outermost cart, the delivery pipe  15  pivots about that cart in a path illustrated by dashed arc  315  in FIG.  20 C. (Dashed arc  315  has been exaggerated for illustrative purposes.) Upon completing the course correction, operation of the outermost cart resumes and the delivery pipe  15  travels in a straight line to point (s,p), as shown by dotted line  316 . Consequently, delivery pipe  15  will actually be headed at a slightly steeper slope away from the water main  11  than that calculated to be the “Present Travel Direction.” Plc  160  may compensate for this slight error by multiplying the previous course correction by a constant number and then multiplying the calculated “Present Travel Direction” by that result to obtain the actual heading of delivery pipe  15 . 
     Travel direction adjustments are preferably implemented at two positions of the water delivery pipe assembly  15  while the connector  18  is engaged to any given access valve  12 . The two positions are distinct because at these positions two different sets of coordinates for the position of cart  14   a  are obtained. At these two positions, the swing arm length measuring device  208  and plc  160  are the only navigational hardware necessary to obtain the precise location of cart  14   a  and subsequently of water delivery pipe assembly  15 . The first position and the derivation of the resultant coordinates has been previously discussed and is shown generally in FIG.  16 A and specifically as “Position  1 ” in FIG.  20 A. In “Position  1 ,” coupling to access valve  12   a  has just taken place prior to any forward travel of delivery pipe assembly  15 . 
     The second position is shown generally in FIG.  16 B and is shown as “Position  2 ” in FIG.  20 B. Here plc  160  may interpret information from swing arm length measuring device  208  and determine that delivery pipe assembly  15  has attained the closest proximity to an access valve  12 . At this closest proximity, delivery pipe assembly  15  is exactly longitudinally aligned with the swing arm  16 . Therefore, swing arm  16  will be exactly perpendicular to the travel direction of delivery pipe assembly  15 . (Plc  160  may actually distinguish this positioning by recognizing the initial condition where the distance between delivery pipe assembly  15  and access valve  12   r  has just begun to increase again.) The distance between cart  14   a  and access valve  12   r  has been determined from the information supplied by encoder  115  of the swing arm length measuring device  208  and is shown in FIG. 20B as “Distance H.” “Distance G” has already been supplied during the previous positioning where coordinates (s,p) were derived. 
     Given that the line representing “Distance H” is perpendicular to the travel direction of delivery pipe assembly  15  and thus perpendicular to a line between the present position of cart  14   a  and the previous position of cart  14   a  at coordinates (s,p), the length of this line designated “Distance J” may be calculated using the Pythagorean Theorem. Therefore, the lengths “Distance G,” “Distance H” and “Distance J” have all been established. With the three lengths of the sides of the triangle known, and the coordinates of access valve  12   r  and the previous coordinates (s,p) of cart  14   a  also known, the coordinates of cart  14   a  in “Position  2  are calculated by plc  160 . Subsequently the travel direction of delivery pipe assembly  15  may now be adjusted at “Position  2 ” according to the previously described procedure as shown in FIG.  20 C. 
     Pivot angle measuring device  165  may measure the angular alignment between the swing arm  16  and the first span  13   a  of the water delivery pipe assembly  15  to alternately act as a travel direction determiner  270 . However, this approach involves more hardware and is subject to inaccuracies related to misalignments along the delivery pipes  13  of the water delivery pipe assembly  15 . 
     When the Water delivery pipe assembly  15  travels to the position shown in FIG. 16C, the trolley assembly  39  and coupler body  24  are located at the outward end of swing arm length adjuster  30 , thus triggering the end-of-travel limit switch  212  to generate a signal. The signal from end-of-travel limit switch  212  instructs plc  160  to terminate operation of drive motors  152  and  157  as dictated by percentage timer  156 . Forward travel of the water delivery pipe assembly  15  halts. (The signal from end-of-travel limit switch  212  may also indicate to zero trolley encoder  115 , providing to maintain accuracy of encoder  115  if encoder  115  is of the incremental variety. Alternately, usage of an absolute type encoder may eliminate the need for limit switch  212 .) Plc  160  now controls the connector  18  according to logic  170 , to operate the valve coupler  19  and transporter  22 . This is done in order to disconnect and transport the coupler body  24  across the ground to a position above the next access valve  12   b  as shown in FIG.  16 D. 
     Just prior to actuation of limit switch  212 , plc  160  may interpret the trolley position along tracks  91  according to trolley encoder  115  and initiate the closure of main water valve  280 . Main water valve  280  may be a commercially available bladder type or butterfly type opening and closing water valve. Main water valve  280  may be configured to close at a slow rate over a time period around 45 seconds and to open more quickly as is preferable to commune with a typical water supply main pump  184  (FIG.  18 ). 
     Responsive to the triggered end-of-travel limit switch  212  and upon receiving a signal from a water pressure sensor  285  indicating that main water valve  280  has completely closed, plc  160  begins disconnection from access valve  12   a  by powering electrically actuated down solenoid  168  and by switching on the fast speed solenoid  203 . With the down solenoid  168  actuated, the pressure side of a hydraulic pressure device  169  is connected to the set of hydraulic cylinders  45  (FIG.  15 ). Hydraulic pressure device  169  includes commonly available electrically powered pump and tank means for supplying fluid under pressure for operation of the hydraulic cylinders  45 . The fluid from pressure device  169  serves to extend hydraulic cylinders  45 . Extending hydraulic cylinders  45  lowers the transport wheel legs  20  along with transport wheels  21  and consequently raises the valve coupler body  24 . When transport wheels  21  contact the ground and coupler body  24  begins to raise, that movement is detected by secondary limit switch  60  as part of vertical position measuring device  50 . Plc  160  interprets the signal from limit switch  60 , halts operation of down solenoid  168  and checks whether either coupler right limit switch  206  or coupler left limit switch  195  are actuated indicating that the coupler body  24  is not centered along the valve coupler adjuster  35 . Actuated coupler switch left  195  or actuated coupler switch right  206  instruct plc  160  to power wheel motors  88  of transport  22  in the necessary direction via forward solenoid  172  or reverse solenoid  234  in unison with medium speed solenoid  191  to deactuate valve coupler adjuster  35 . When either coupler switch left  195  or coupler switch right  206  is no longer actuated, plc  160  resets to zero the distance measured by pivot angle encoder  190 . (The centering of coupler body  24  along coupler adjuster  35  slightly improves the accuracy of the ensuing measurement of the distance between access valves as measured by pivot angle encoder  190  in the utilization of access valve locator  48  as shown in FIGS. 13 and 14.) Plc  160  then switches off the just activated forward solenoid  172  or reverse solenoid  234  as well as medium speed solenoid  191  and switches on fast speed solenoid  203  and reactivates down solenoid  168 . The swing arm outer end now raises at full speed until a leg down limit switch  216  triggers telling plc  160  that the swing arm outer end is fully raised off of the access valve. Plc  160  then switches off down solenoid  168 . 
     When hydraulic cylinders  45  are fully extended, the connector  18  is positioned similar to the position shown in FIG. 1 except that the valve coupler  19  will be in a mostly vertical alignment with the access valve  12 . 
     With the transport wheels  21  in the lowered position, the transporter  22  is operated by plc  160  which now actuates forward solenoid  172  to power the drive motors  88  in a forward direction. Fast speed solenoid  203  remains in operation from its use during the previous operation of lowering the transport wheels  21 . Drive motors  88  power the transport wheels  21  in order to forwardly move the swing arm outer end with the valve coupler  19 . The swing arm outer end moves along the ground in an arc path as indicated by arrow  87  shown in FIG. 16D about pivot  17  (FIGS.  11  and  13 ). (If delivery pipe  15  is traversing the field in the direction opposite that shown, plc  160  will actuate reverse solenoid  234  in place of forward solenoid  172  to move the swing arm outer end in the reverse direction between access valves.) 
     Coinciding with initiating forward travel, plc  160  also switches on trolley-in-solenoid  204 . Consequently, trolley assembly  39  travels toward the inner end of rails  91 . Trolley travel continues until positioned along the tracks as shown in FIG. 1A where position information from trolley encoder  115  instructs plc  160  to switch off trolley-in-solenoid  204 . The trolley assembly  39  and in particular detector plank  41  are now appropriately positioned to detect the next access valve  12   b.    
     Arc travel of the swing arm outer end continues at a speed approaching the capacity for the associated structure, around  2  miles per hour, until plc  160  interprets the change in angle as registered by angle encoder  190  to be such that the next access valve  12   b  is close ahead. In response, plc  160  switches off fast speed solenoid  203  and switches on medium speed solenoid  191 . Consequently, drive motors  88  operate at a much slower r.p.m. and forward travel of the swing arm outer end is reduced to around 0.5 miles per hour in anticipation of stopping travel. 
     Arc travel of the swing arm outer end continues at the medium speed forward rate until plc  160  interprets the change in angle as registered by angle encoder  190  to be such that the detector plank  41  is now positioned directly above access valve  12   b . In response, plc  160  switches off forward solenoid  172  and retains activation of medium speed solenoid  191 , in anticipation of the next ensuing procedure. Subsequently the drive motors  88  stop operating. When drive motors  88  stop operating, forward travel of the swing arm outer end also stops. 
     (The distance between access valve  12   a  and access valve  12   b  may typically be  102  feet as would then be the distance between any two successive access valves  12  along water main  11 . Sixty feet is the maximum distance available for the only commercially available automated connector lateral move irrigator.) 
     The valve coupler  19  is now positioned similar to the position shown in FIG. 1, and the connector  18  and water delivery pipe assembly  15  are positioned as shown in FIG.  16 D. In further response to the change in pivot angle as registered by the pivot angle encoder  190 , plc  160  switches on up-solenoid  179 . The up-solenoid  179  connects hydraulic cylinders  45  to the intake side of hydraulic pressure device  169  causing hydraulic cylinders  45  to retract and subsequently cause transport legs  20  with transport wheels  21  to be pivoted upward. The upward pivoting legs  20  and transport wheels  21  cause the swing arm outer end including valve coupler body  24  to move in a downward direction. The swing arm outer end is lowered until valve detector plank  41  makes contact with the top edge of access valve  12   b  as is indicated by detector plank limit switch  42 , functioning as vertical position measuring device  50  and valve detector  40  as shown in FIGS. 2,  2 A and  14 . Responsive to limit switch  42 , plc  160  acts to switch off up-solenoid  179  and as a result hydraulic cylinders  45  stop retracting and the swing arm outer end ceases to lower and is positioned as shown in FIGS. 2 and 2A. 
     Valve coupler  19  is now vertically positioned to utilize the access valve catcher  135  (FIGS.  7 - 9 ). In further response to the actuation of detector plank limit switch  42 , plc  160  now switches on trolley out solenoid  194 . Subsequently trolley motor  111  operates to propel trolley assembly  39  including coupler body  24  and “v”-configured catcher  137 , outwardly along rails  91  as part of the above-described access valve catcher  135 . Outward travel continues until access valve body  97  triggers catcher limit switch  140  as part of horizontal position measuring device  145  (FIG.  14 ). Outward travel further continues until both plastic pads of “v”-configured catcher  137  are in contact with valve body  97 . Plc  160  maintains active out-solenoid  194  to maintain contact between “v”-configured catcher  137  and access valve body  24  which serves to maintain plastic alignment cone  85  appropriately positioned directly above access valve body  97  (FIGS. 3 and 3A) and hold plastic cone  85  vertically aligned with coupler body  24  during further lowering of coupler body  24 . 
     Plc  160  responds to activated catcher limit switch  140  by switching on up-solenoid  179  (medium speed solenoid  191  remains on). Consequently hydraulic cylinders  45  retract and the swing arm outer end lowers until vertical position detector wheel  57  contacts pivot pad  167  and continues lowering until a signal from primary vertical position limit switch  59  of vertical position measuring device  50  (FIG. 14) indicates to plc  160  that the swing arm outer end has been sufficiently lowered so that the upper rim of access valve body  97  is well inside the cone cavity of plastic alignment cone  85 . Plc  160  responds to the signal from primary limit switch  59  by switching off trolley out-solenoid  194  thus terminating pressurized oil flow to trolley motor  111 . In an unpowered state, trolley motor  111  freewheels as allowed by an “open spool” configured valve body  299  as shown in the hydraulic circuit of FIG.  15 . Thus trolley assembly  39  may be freely moved along rails  91  as required during alignment of coupler body  24  to valve body  97 . 
     Activation of primary vertical position limit switch  59  also instructs plc  160  to open main water valve  280 . Main water valve  280  then begins to open in anticipation of water flow from access valve  12   b.    
     Downward travel of swing arm outer end including coupler body  24  and plastic cone  85  continues as cone  85  meets and mates with the upper rim of valve body  97  effecting to gradually center coupler body  24  directly over the upper rim of valve body  97 , functioning as the valve coupler aligner  100  (FIG.  10 ). Lowering continues as coupler body  24  slides over valve body  97  effectively locking coupler body  24  to valve body  97 , functioning as coupler lock  350  (FIG.  10 ). Downward travel continues and actuator  29  (FIG. 10) is utilized to open access valve  12   b  and water begins flowing through connector  18  and water delivery pipe assembly  15 . Further downward travel activates secondary limit switch  60  of vertical position measuring device  50  (FIG. 14) alerting plc  160  that ground support wheels  27  are almost in contact with pivot pad  167 . Plc  160  responds to limit switch  60  by switching on fast-speed-solenoid  203  and switching off medium-speed-solenoid  225 . Transport wheel legs  20  are raised quickly off of the ground until triggering leg-up limit switch  205  which indicates that the transport wheels  21  have been fully raised off of the ground. In response, plc  160  switches off fast-speed solenoid  203  and also switches off up-solenoid  179 . 
     When hydraulic cylinders  45  are completely retracted as shown in FIGS. 4,  4 A and  5 , support wheels  27  have contacted the ground to support the swing arm outer end. Transport wheels  21  have been lifted off the ground surface and the valve  12   b  is open. Water flows from opened access valve  12   b  through the connector  18 , through water delivery pipe assembly  15 , and subsequently through water applicator  143  and onto the crop. In further response to a signal from leg-up limit switch  205 , plc  160  may once again initiate forward travel and subsequent water application by the water delivery pipe assembly  15  by again powering drive motors  152  and  157  in response to input from percentage timer  156 . 
     Connector  18  and water delivery pipe assembly  15  have now in effect been controlled to operate for one complete cycle of forward travel. Further forward travel and subsequent application of water will result by repeating the previously described operational procedure. Successive repetitions of the aforementioned operation correlating with each successive connection to an access valve  12  along the water main  11 , enables the water delivery pipe assembly  15  to transverse and apply water across a field until connection is made to the last access valve  12   d  (FIG.  17 B). Irrigation from water delivery pipe assembly  15  commences and continues about access valve  12   d  in the usual manner until a trip bar  180  mounted to cart  14   e  as shown in FIG. 11, engages a barricade  181  (FIG. 17B) subsequently signaling plc  160  to disregard percentage timer  156  and no longer power drive motors  152  and  157  thus halting forward travel of water delivery pipe assembly  15 . (Barricade  181  is positioned in the travel path of the wheels of movable cart  14   e  so that if drive motor  157  fails to be shut off, the barricade will stop the cart  14   e . Trip bar  180  as well as barricade  181  are commonplace to the industry.) 
     Plc  160  also responds to actuation of trip bar  180  by operating the main water valve  280 . Main water valve  280  slowly closes until no water is flowing through connector  18 , water delivery pipe assembly  15  and water applicator  143 . With main water valve  280  closed, pressure will rise in water main  11  as detected by pressure sensor  186  which then activates a timer  183  (FIG. 18) that acts as a safety device. When connector  18  is being controlled to travel between successive access valves  12  and connector  18  subsequently fails to make connection to a next successive access valve  12  within a specified time, timer  183  will automatically shut off main pump  184 . Consequently, a certain length of time after main water valve  280  has been completely closed, main pump  184  will automatically shut down. 
     The connector  18  and water delivery assembly  15  now remain idle until the farmer decides to initiate rotation of the connector  18  and delivery pipe assembly  15  to the adjacent field on the opposite side of water main  11 , Field B. 
     To rotate connector  18  and delivery pipe assembly  15 , the farmer manually latches adjustable trolley hitch  226  to basebeam tongue  231  with pin  227  (FIG.  5 ). Consequently trolley assembly  39  has been locked to basebeam  123  and trolley assembly  39  will no longer freewheel along rails  91 . The farmer now manually prescribes a rotate direction in control panel  310  (FIG.  14 ), typically reverse, and plc  160  begins operation of the delivery pipe rotator  103 . Plc  160  switches drive motor  157  to a full speed reverse setting. Consequently, movable cart  14   e  begins forward travel in a reverse direction. The remaining carts  14 , with the exception of cart  14   a , along the water delivery pipe assembly  15  remain longitudinally aligned with the last span  13   e  during operation of the delivery pipe rotator  103  by utilizing the same conventional means of alignment as utilized for that purpose during operation of the connector  18 . 
     The alignment of supply pipe  36  to span  13   a  during operation of the delivery pipe rotator  103  is maintained by plc  160  with alignment information provided by angle encoder  190 . At the onset of delivery pipe rotator  103 , plc  160  reads the position at angle encoder  190 , presuming span  13   a  to be longitudinally aligned to supply pipe  36 . Plc  160  then monitors angle encoder  190  during operation of the delivery pipe rotator  103 . When the information from angle encoder  190  suggests span  13   a  and supply pipe  36  to be sufficiently misaligned, plc  160  will switch on drive motor  152  in the appropriate (reverse) direction until supply pipe  36  and span  13   a  are once again aligned. 
     Operation of the delivery pipe rotator  103  is continued, until the water delivery pipe assembly  15  and swing arm  16  reach a position as shown in FIG.  17 C. There the arm of trip bar  180  engages barricade  181  positioned at the end of the circular travel path of cart  14   e . The trip bar  180  signals plc  160  indicating that operation of the delivery pipe rotator  103  may be discontinued. Plc  160  switches off drive motor  157 . Subsequently the connector  18  may once again be operated. In order to do so, the farmer removes pin  227  thus releasing the trolley hitch  226  from the basebeam tongue  231 , and also switches on forward irrigation in control panel  310  (FIG. 14) and restarts the pump  184 . 
     With additional programing of logic  170 , and a motor brake for locking trolley motor  111  from rotating, the transition from water delivery pipe travel to water delivery pipe rotation and back to delivery pipe travel again can be automated. 
     As shown in FIG. 17C, the delivery pipe rotates in a reverse direction in relation to the previous forward linear travel of the delivery pipe assembly  15 . In some cases, it may be advantageous to rotate the water delivery pipe assembly  15  in the forward direction. Consequently, operation of the delivery pipe rotator  103  would result in the water delivery pipe assembly  15  rotating beyond Fields A and B in order to achieve the necessary position to begin operation of the connector  18  and subsequent irrigation. 
     With the addition of a center pivot sprinkler set  311  as part of water applicator  143  (FIGS.  13  and  14 ), water delivery pipe assembly  15  is operable to apply water while rotating about an access valve. Water can be applied while rotating delivery pipe  15  in either rotation direction between Fields A and B. Consequently, delivery pipe  15  may be operated to irrigate both as a lateral move irrigator and as a center pivot irrigator. Center pivot sprinkler set  311  includes a set of individual sprinklers  314  as shown in FIG.  13 . Sprinklers  314  are mounted along the water delivery pipe  15  and also along underboom  260  and are configured to accommodate the need to linearly increase water output approaching the outer end (remote from access valve  12 ) of water delivery pipe  15 . This configuration of sprinklers  314  of center pivot sprinkler set  311  is typical to center pivot irrigators and thus commonplace to the industry. Sprinkler solenoid valves  313  shown in FIG. 13 are mounted between sprinklers  314  and delivery pipe  15  to allow or restrict water flow through sprinklers  314 . The farmer, when initiating the rotation of delivery pipe  15  in control panel  310 , also manually initiates irrigation during that rotation. In response to the farmers instruction, plc  160  operates solenoid valves  313  to allow water to flow through sprinklers  314 . At the same time, plc  160  operates sprinkler solenoid valves  292  of a lateral move sprinkler set  312  to halt water flow through sprinklers  291 . (Sprinklers  291  were in operation during the preceding lateral travel of delivery pipe  15  along the succession of access valves  12 .) Plc  160  also operates main water valve  280  to allow water to flow through delivery pipe  15  as required to irrigate during rotation. (Lateral move sprinkler set  312  could be utilized by itself to accommodate both lateral and center pivot irrigation by simply terminating water flow to an increasing number of the sprinklers  291  approaching the inner end of delivery pipe  15  during center pivot irrigation. This approach would be somewhat more affordable in equipment cost. However, the sprinkler configuration would not be tailored specific to center pivot irrigation and water application efficiency during center pivot operation would be less efficient as a result.) 
     Water delivery pipe assembly  15  may now begin forward travel across Field B. (With the resumption of lateral move irrigation, plc  160  reinstates operation of lateral move sprinkler set  312  and discontinues operation of center pivot sprinkler set  311  providing that sprinkler set  311  was in use during the preceding rotation of delivery pipe  15 . Also, if delivery pipe  15  is not equipped with a sprinkler set  311  to incorporate center pivot irrigation, sprinkler set  312  will not require solenoid valves  292  to control water flow through sprinklers  291 .) The water delivery pipe assembly  15  travels from the starting position as shown in FIG. 17C until the unit arrives at a position similar to that shown in FIG.  16 C. The transporter  22  and valve coupler  19  are now operated by plc  160  in order to forward the connection to the next access valve  12  as shown in FIG.  16 D. 
     Water delivery pipe assembly  15  travels forward in conjunction with the repetitive operation of the connector  18 , each repetition corresponding with each successive disconnection from an access valve  12 . Travel transpires from the position at one end of the series of access valves  12  as shown in FIG. 17C to the position at the other end of the series of access valves  12  as shown in FIG.  17 D. Once again, an end of field barricade  181  has been placed in the path of travel cart  14   e  and trip bar  180  engages barricade  181  which sends a signal to plc  160  indicating that the field end has been reached. The last access valve  12  available for connection during the irrigation of Field B is access valve  12   c . Access valve  12   c  was the first access valve  12  to be connected to and opened at the onset of the irrigation process when the water delivery pipe assembly  15  began forward travel to irrigate Field A as shown in the aforementioned position in FIG.  17 A. 
     From the position shown in FIG. 17D, the swing arm  16  and water delivery pipe assembly  15  may be rotated substantially  180  degrees about the connection to access valve  12   c  to the position shown in FIG.  17 A. The delivery pipe rotator  103  is again operated by plc  160  according to the same operational procedure employed for rotating the swing arm  16  and water delivery pipe assembly  15  from the position shown in FIG. 17B to the position shown in FIG.  17 C. Operation of delivery pipe rotator  103  is terminated when trip bar  180  engages another appropriately positioned end of field barricade  181 . Actuation of trip bar  180  signals plc  160 , which in response, discontinues operation of the water delivery pipe rotator  103  and resumes operation of the connector  18 . 
     Both Field A and Field B have now been irrigated and the water delivery pipe assembly  15  is positioned to begin a second irrigation of Field A. The circuitous nature of the path traveled by the water delivery pipe assembly  15  of the present invention presents a distinct advantage over the travel path of suggested automated irrigation approaches including present commercially available approaches with the exception of my earlier patented irrigator (U.S. Pat. No. 4,877,189). Irrigation of a field with present commercially available automated lateral move irrigators leaves the water delivery pipe the full length of the field away from the original starting position. Presently available automated lateral move irrigators must then be rolled dry or while irrigating, backwards across the field. 
     The distance traveled, and the area covered by the present system of rotating the water delivery pipe assembly between fields and back to the original starting position, is superior to the commercially available approaches. 
     The most dramatic advantage associated with the present system also emerges from the circuitous nature of the path traveled by the water delivery pipe assembly. Many fields to be irrigated by presently available automated lateral move irrigators may now be irrigated with a water delivery pipe assembly  15  that is only half of the previously required pipe length. In addition, the number of access valves installed for operation of the present system will typically be about three fifths that required with prior commercially available systems. 
     When the coupler  19  is transported between access valves  12  (FIG. 16D) and when the delivery pipe rotator  103  is operated (FIGS.  17 C and  17 A), water flow through the water delivery pipe assembly  15  has been discontinued. Typically the pump would remain shut off when the delivery pipe rotator is operated. However, for the short duration of time required to forward access valve connection between two access valves, in many cases it is preferable to keep the pump operating and temporarily continue to flow a minimal amount of water to cool the pump. Typically, only about one percent of the water pumped needs be diverted for cooling purposes. 
     A preferred approach for diverting water from water main  11  is shown in FIG. 18. A water main diverter valve  185  is hydraulically connected somewhere along the water main  11  preferably near one of its ends. Water main diverter valve  185  is operated to open in response to a signal from a water main pressure sensor  186 . Water main pressure sensor  186  monitors the pressure in the water main  11 . When water flows through the water delivery pipe assembly  15  has been discontinued, the pressure in water main  11  rises dramatically as the pump continues to operate. Water main pressure sensor  186  detects the obvious pressure rise and responds by signaling the water main diverter valve  185  to open. When the water main diverter valve  185  is opened, water from water main  11  flows into a gravity applicator pipe  187 . Gravity applicator pipe  187  may be a common piece of pipe running from the water main diverter valve  185  along the elevationally high side of a comparatively small irregular shaped field in the vicinity of the much larger Fields A and B as shown in FIGS. 17A-17D. Gravity applicator pipe  187  includes spaced outlet holes along its length which allow the intermittently supplied water to flow freely from the holes and into adjacent furrows extending out and downward into the adjacent small field. Utilizing a gravity applicator pipe is common to the gravity fed irrigation systems. Alternately, for many installations, instead of diverting water into a gravity applicator, the water could simply be dumped back down a well or back into the water source such as a river. 
     For some applications, another alternative is to divert the water into a small reservoir and subsequently pump the water back into the water main (not shown) when water is again flowing into and through the water delivery Pipe assembly  15 . 
     The previously discussed sway inhibitor  130  enables the valve coupler  19  to be transported between valves at a much faster speed. Consequently, the amount of time water flow through water main  11  need be halted is reduced accordingly. As a result, many pumps which previously required flow diversion such as shown in FIG. 18, may now operate for this reduced amount of time without the need for the cooling water provided by flow diversion. Therefore, sway inhibitor  130  eliminates the need for and, thus, eliminates the cost and complexities of flow diversion in many instances. 
     The present system may also operate along a series of spaced access valves  12  mounted to a water main  11  wherein the water main  11  may elbow at a right angle in order to irrigate an L-shaped field or the water main  11  may elbow more than once incorporating a number of right angles (not shown). The elbows need not be right angles. Water mains other than straight maintain the characteristic of enabling circuitous travel irrigation of the water delivery pipe assembly  15 . 
     For many irrigated lands, the optimum amount of water to be applied will vary in accordance with varying terrain and also varying soil types. For example, in most cases valleys will require less water applied than the adjacent hilltops. Therefore, it is often advantageous to vary the amount of water applied to account for the varying conditions. In addition, a farmer may chose to plant different crops thus with differing water requirements in the same field. 
     Additional controls may be incorporated with the present invention to selectively vary the amount of water applied about the area to be irrigated during lateral travel of the delivery pipe  15 . A controllable sprinkler set  290  (FIGS. 13 and 14) may be employed in conjunction with plc  160  to selectively control the water flow from a set of sprinklers as part of the water applicator  143 . Controllable sprinkler set  290  may utilize solenoid valves and sprinklers mostly identical to solenoid valves  292  and sprinklers  291  previously discussed for the operation of sprinkler set-A  312 . Solenoid water valves  292  are typically open to water flow and may be closed upon activation of the solenoid by plc  160 . Each sprinkler  291  is positioned along water delivery pipe assembly  15  so as to overlap its spray discharge pattern with those of adjacent sprinklers. Six to eight sprinklers may be collectively applying water to any one given spot. 
     Water flow through the sprinklers  291  may be restricted in a variety of ways. For example, the solenoid valve  292  of every other sprinkler could be closed when positioned over a selected area. Alternately, water flow through every third or every fourth solenoid valve  292  and thus sprinkler  291  may be discontinued and so on. Another option is to modulate the operation of desired sprinlders. In other words, to open and close prescribed solenoid valves  292  for timed periods over the ground specified to receive less water. This option would enable a finer adjustment compared with simply closing said solenoid valves. 
     Logic  170  is preferably programmable so that plc  160  will keep track of the geographic position of the water delivery pipe assembly  15  by keeping track of each connection to an access valve  12 . For example, plc  160  will recognize the beginning of a field such as Field A as shown in FIG.  17 D. The first access valve  12  of Field A as well as all access valves  12  will be designated an access valve number as part of an access valve identifier  302 . A farmer initiating irrigation of Field A will manually enter the number (which corresponds to the first access valve  12  of Field A) into an access valve number input  135  of a manual programming keypad  240 . Keypad  240  may preferably be electrically connected to plc  160 . If for some reason the irrigation cycle is to be initiated somewhere other than at a field end, the number corresponding to the access valve  12  presently connected to connector  18  and subsequently water delivery pipe assembly  15  will be entered into the access valve number input  135  of manual programming keypad  240  by the farmer. 
     Plc  160  may recognize the beginning of Field B in the same way with the farmer entering the access valve number into the access valve number input  135 . Once an access valve number has been supplied to the access valve number input  135 , plc  160  may then utilize an access valve counter  301  which is also part of access valve identifier  302 . Access valve counter  301  incorporates programming in logic  170  enabling plc  160  to recognize and subsequently count each successive connection by connector  18  to an access valve  12  along the succession of access valves  12  of water main  11 . Utilizing the access valve number input  135  in combination with the access valve counter  301 , plc  160  may keep track of the general geographic position of water delivery pipe assembly  15 . 
     Alternately, the access valve identifier  302  may incorporate a bar code or some other identifying mark on each access valve, thus enabling plc  160  to determine the particular unique identity of that access valve and in that way keep track of the general geographic position of water delivery pipe assembly  15 . With this approach the farmer is not required to make an entry into the access valve number input  135 . This approach in effect replaces the combined workings of the access valve number input  135  and the access valve counter  301 . 
     Plc  160  may further accurately track the geographic position of water delivery pipe assembly  15  by utilizing information available from the previously discussed swing arm length measuring device  208  as part of delivery pipe navigator  210 . The information from swing arm length measuring device  208  may be utilized by plc  160  in the operation of an inter access valve measuring device  303 . 
     Inter access valve measuring device  303  serves to measure the travel of the water delivery pipe assembly  15  after connection has been made to an access valve  12  and subsequently after that particular access valve  12  has been counted. As previously discussed, the exact geographic position of cart  14   a  may be derived when the water delivery pipe assembly  15  is positioned as illustrated in FIGS. 16A and 20A and also when positioned as shown in FIGS. 16B and 20B. The distance of cart  14   a  from the water main  11  and thus from the “Preferred Travel Path” will vary within plus or minus approximately  12  inches and is not a significant concern. The position of cart  14   a  and thus water delivery pipe assembly  15  along the length of the “Preferred Travel Path” is the significant measurement for the purpose of selectively varying water application. Given a distance of  102  feet between access valves, the exact position of cart  14   a  is known by plc  160  roughly every 51 feet. When the delivery pipe assembly  15  travels the approximate 51 feet from the position shown in FIGS. 16A and 20A to the position shown in FIGS. 16B and 20B, the trolley assembly  39  travels from a position at the outer end of rails  91  (FIG. 4A about 20 feet along rails  91  to a position at the inner end of rails  91  (FIG.  5 A). When the water delivery pipe assembly  15  travels the 51 feet between the position shown in FIGS. 16B and 20B to the position of FIGS. 16D and 20A, the trolley assembly  39  travels about 20 feet along rails  91  from the inner end of rails  91  back to the outer end of rails  91 . Plc  160  may utilize the swing arm length measuring device  208  and subsequently monitor trolley encoder  115  as the trolley assembly  39  travels along the rails  91  between the two positions where exact coordinates are known. Plc  160  will convert the travel of the trolley assembly into an approximation of the travel of cart  14   a  and thus of the water delivery pipe assembly  15 . This approximation of the travel of delivery pipe assembly  15  is added to the previous position where exact coordinates were determined and consequently at any given moment, the position of water delivery pipe assembly  15  may be estimated by plc  160 . Consequently, the geographic position of water delivery pipe assembly  15  along the “Preferred Travel Path” may be tracked by plc  160  with an accuracy within inches of the exact position. 
     Manual programming keypad  240  may also be utilized to enable the farmer to manually program in the sprinklers positioned along the length of the water delivery pipe assembly  15 . Each sprinkler is preferably designated a sprinkler number. Manual programming keypad  240  further enables the farmer to program sprinkler operation as the water delivery pipe assembly  15  travel across a field. The farmer may program certain solenoid water valves  292  to be closed when sprinklers  291  associated with those valves are located above areas that have previously received an excess amount of irrigation water such as valley areas as discussed. Plc  160  will catalog the number of the sprinkler as entered by the farmer as well as the exact geographic position of water delivery pipe assembly  15  at each position where the farmer programs a change in sprinkler operation. The farmer may also program different settings for percentage timer  156  in conjunction with any location of water delivery pipe assembly  15 . During operation, plc  160  serves to implement the individual percentage timer settings and also the variations in sprinkler operation as programmed by the farmer. These implementations correspond to plc  160  counting and thus keeping track of the appropriate access valves as well as tracking the exact geographic position of the water delivery pipe assembly  15  by monitoring the position of the trolley assembly  39  along rails  91 . 
     An access valve electronic detector  445 , illustrated in FIGS. 14,  21 A and  21 B, can be employed by the present invention as part of valve coupler  19 . Access valve electronic detector  445  can be employed to function as any or all of: access valve locator  48 , access valve detector  40 , access valve catcher  135 , horizontal position measuring device  145 , valve coupler aligner  100  and vertical position measuring device  50 . 
     In the example embodiment shown in FIGS. 21A and 21B, access valve electronic detector  445  provides to function as all of the suggested components: locator  48 , detector  40 , device  145 , catcher  135 , aligner  100  and measuring device  50 . Access valve electronic detector  445  as shown includes four metal sensors  446   a  through  446   d . (Detector  445  can alternately employ sensors which sense other than metal such as plastic, concrete etc. Also, a triangular arrangement of three sensors, or some other number and arrangement of sensors can be employed.) Sensors  446   a  through  446   d  are directionally aimed to electronically sense the presence of valve material beneath them. (For this example, access valve  12  is constructed of steel which is sensed). Each of sensors  446   a  through  446   d  is electrically connected to programmable logic controller  160  and each provides plc  160  with signal information regarding an access valve  12 . The strength of the signal from each sensor  446   a  through  446   d  correlates to the proximity of each sensor to an access valve  12 . The stronger the signal, the closer the access valve  12 . 
     In accordance with programming, plc  160  provides analysis of the signal information from sensors  446   a  through  446   d  and responds when appropriate. As transporter  22  transports swing arm  16  with coupler  19  from one access valve  12  to the next forward access valve  12 , the presence of the next forward access valve  12  causes one (or more) of the sensors  446   a  through  446   d  to provide a signal to plc  160 . Plc  160  recognizes this signal as a detection of the access valve  12  and, thus, access valve electronic detector  445  here provides the functions of both access valve locator  48  and access valve detector  40 . (For this example of electronic detector  445 , in anticipation of the next forward access valve  12 , the positioning of trolley  39  along rails  91  is modified from that shown in FIG.  1 A. Trolley  39  is for this employment now positioned much closer to end beam  196  such that the coupler body  24  is positioned to reside approximately directly above the access valve  12  when the swing arm  16  with coupler body  24  is transported over the access valve  12 .) 
     After detection of the access valve  12 , plc  160  continues monitoring the information from sensors  446   a  through  446   d  to now align the access valve  12  with valve coupler body  24 . When the signal strengths from sensors  446   a  and  446   b  indicate that the next forward access valve  12  is approximately centered between them, plc  160  responds by halting the forward travel of transporter  22 . As such, electronic detector  445  has provided to function as valve catcher  135  by “catching” the valve  12 . Through determining that access valve  12  is approximately centered between sensors  446   a  and  446   b , electronic detector  445  here also has provided the function of horizontal position measuring device  145  which is to determine an orientation between an access valve  12  and valve coupler  19 . Plc  160  now evaluates the signal strengths from sensors  446   c  and  446   d  and responds by controlling the powering of trolley  39  along rails  91  as needed (FIG. 1 a ) to move coupler body  24  inward or outward to center coupler body  24  over the access valve  12 . As such, again electronic detector  445  has provided the function of valve catcher  135 . Upon determining that the proper centering of coupler body  24  over access valve  12  has been achieved, electronic detector  445  again has provided the function of horizontal position measuring device  145 . 
     After “catching” the access valve  12  and after determining that the access valve  12  has been caught, access valve electronic detector  445  now provides the function of aligner  100 . Plc  160  implements the lowering of coupler body  24  onto the access valve  12  while continuing to monitor the information from sensors  446   a  through  446   d . In response to the information, plc  160  employs the travel of trolley  39  and the travel of coupler adjuster  35  and/or transporter  22  as needed to maintain coupler body  24  centered over the access valve  12  until body  24  is locked onto valve  12 . As such, the function of aligner  100  is provided. 
     Also after catching the access valve  12  and determining that the access valve  12  has been caught, electronic detector  445  now provides the function of vertical position measuring device  50 . Upon plc  160  initiating the lowering of coupler body  24  onto valve  12 , plc  160  monitors the information from sensors  446   a  through  446   d  to determine the proximity of coupler body  24  to access valve  12 . (Valve  12 , including flange  79 , and flange  80  are all fabricated out of steel, the steel sensed by sensors  446   a  through  44   d .) Plc  160  evaluates the increasing signal strengths from all of the sensors  446   a  through  446   d . When the signal strengths reach a first determined level, plc  160  responses as if the primary limitswitch  59  has been activated (primary limitswitch  59  previously discussed, FIG.  14 ). When the signal strengths reach a second determined level, plc  160  responses as if the secondary limitswitch  60  has been activated (secondary limitswitch  60  previously discussed, FIG.  14 ). In other words, the determined signal strength level equates to the coupler body being positioned above the valve  12  where the limitswitch  59  or limitswitch  60  would previously have engaged. Accordingly, electronic detector  445 , functioning as vertical position measuring device  50 , takes the place of limitswitch  59 , limitswitch  60  and the associated mechanical mechanism. 
     In the above example embodiment, electronic detector  445  was described configured to sense an access valve  12 . Electronic detector  445  can alternately be configured to sense any part of an access valve assembly  400 . An example of assembly  400  is shown in FIG.  10 . Assembly  400  of FIG. 10 includes access valve  12 , riser pipe  82 , flange  80  and pivot pad  167 . Electronic detector  445  can be configured to sense any or all of these components or the materials they are fabricated from. 
     As another example, access valve assembly  400  includes other components or materials such as a metal object or objects, a magnet or magnets or other, these buried in the concrete of pivot pad  167 . Electronic detector  445  is then configured to sense them. As another example, access valve assembly  400  includes components or materials such as a metal object or objects, a magnet or magnets or other, these located outward of pivot pad  167  relative to the associated access valve  12  and in the near vacinity of pivot pad  167  such that the wheels  21  (FIG. 1A) of transporter  22  roll to the outside of them relative to the associated access valve  12 . Electronic detector  445  is then configured to sense the components or materials. In accordance with the above examples, access valve assembly  400  is defined to include an access valve  12  and any other component or material positioned such that transport wheels  21  roll to the outside of the component or material relative to the access valve  12 . 
     The mechanical valve catcher  135  discussed earlier and shown in FIGS. 1A,  2 A,  7 ,  8  and  9  acts against a side surface of an access valve  12 . The mechanical catcher  135  can alternately be configured to act against any component or material or facet of the above defined access valve assembly  400 , with the exception of the top rim of access valve  12 . 
     An access valve assembly  400  can be described as a beacon  410  (FIG.  10 ). Beacon  410  provides as a reference object to be sensed by electronic detector  445 . Accordingly, electronic detector  445  references beacon  410  in providing the functions of locator  48 , detector  40 , catcher  135 , measuring device  145 , aligner  100  and measuring device  50 . Beacon  410  can be other than access valve assembly  400  as well. Beacon  410  can be a component or material placed such that transport wheels  21  roll over the component or material. Beacon  410  can also be any component or material placed such that transport wheels  21  roll to the inside of the component or material relative to the access valve  12 . Detector  445  can be configured to sense beacon  410  and provide a one dimensional alignment, a two dimensional alignment or a three dimensional alignment between coupler body  24  and access valve  12 . Detector  445  can be configured to sense beacon  410  and determine a one dimensional, a two dimensional or a three dimensional orientation between body  24  and valve  12 . Beacon  410  is defined to include any component or material capable of being sensed by electronic detector  445 . 
     In compliance with the statute, the invention has been described in language more or less specific as to structural features. It is to be understood, however, that the invention is not limited to the specific features shown, since the construction herein disclosed comprises a preferred form of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims, appropriately interpreted in accordance with the doctrine of equivalents.