Patent Publication Number: US-8973344-B2

Title: Automatic driveshaft coupler for auto header hookup

Description:
FIELD 
     The field is agricultural work vehicles. More particularly the field is shaft couplers for coupling agricultural harvesting heads to harvesting vehicles. 
     BACKGROUND 
     Agricultural work vehicles such as agricultural harvesters travel through agricultural fields harvesting crops. These vehicles are typically arranged into 2 major subcomponents that are selectively coupled together. 
     The first subcomponent is the harvesting vehicle. The harvesting vehicle is configured to gather the cut crop material, thresh the grain, separate the grain from the material other than grain (MOG), clean the grain, and store the grain until it can be unloaded from the vehicle. Harvesting vehicles such as this are typically called “combine harvesters” or “combines”. 
     The second subcomponent is the agricultural harvesting head. The agricultural harvesting head is configured to engage a particular crop or crops as it travels through the field supported on the front of the harvesting vehicle, to separate the crop from the ground, and to convey the crop to the harvesting vehicle. Agricultural harvesting heads are specially configured based upon the crop or crops they are designed to harvest, which typically include such crops as wheat, soybeans, corn, rice, and rapeseed. 
     Agricultural harvesting heads are typically mounted on a support structure called a “feederhouse” that extends forward from the front of the harvesting vehicle. They include components such as conveyor belts, augers, and reciprocating knives that are driven by an internal combustion engine mounted on the harvesting vehicle. 
     To connect the two together, the vehicle operator maneuvers the vehicle until the feederhouse and the agricultural harvesting head are aligned. The operator then climbs down from the harvesting vehicle, approaches the front of the harvesting vehicle, and manually couples the harvesting vehicle and the agricultural harvesting head together. 
     Once the two are connected, the operator then returns to the latter, climbs up to the operator station, and starts the vehicle. This is a time-consuming process. 
     What is needed, therefore, is a more efficient means of coupling the agricultural work vehicle to an agricultural harvesting head. 
     It is an object of this invention to provide such a system. 
     SUMMARY 
     In one arrangement, an agricultural harvester is provided comprising: a self-propelled vehicle; a feederhouse; a driveshaft having a proximal end and a distal end, wherein the driveshaft supported on the feederhouse wherein the proximal end is configured to be driven in rotation to transmit power from the agricultural harvester to an agricultural harvesting head; and a first coupler fixed to the distal end of the driveshaft, the first coupler further comprising a coupler body, a piston disposed inside the coupler body, and a first key mechanically coupled to the piston to be actuated by the piston, the first key being extendable from and retractable into the coupler body when the piston is actuated. 
     The agricultural harvester may further comprise a second hydraulic fluid connector supported on the driveshaft for rotation with respect to the driveshaft. 
     The second hydraulic fluid connector may extend around and seals against an outer surface of the driveshaft. 
     The second hydraulic fluid connector may enclose a hydraulic fluid passageway in the driveshaft that communicates hydraulic fluid from a surface of the driveshaft to the piston. 
     The piston may be disposed in the coupler body to receive hydraulic fluid from the second hydraulic fluid connector and to be actuated thereby. 
     The first coupler may further comprises a second key and a third key that are configured to be simultaneously extendable from and retractable into the coupler body when the piston is actuated. 
     The first key, the second key, and the third key may be equiangularly disposed about a circumference of the coupler body. 
     The agricultural harvester may further comprise the agricultural harvesting head, and the agricultural harvesting head may further comprise a frame; a reciprocating knife mounted on the frame; a second driveshaft having a first end drivingly coupled to the reciprocating knife to drive the reciprocating knife and a second end; and a second coupler fixed to the second end of the second driveshaft, the second coupler having a cavity for receiving the first coupler. 
     An annular trough may be formed in a cylindrical side wall of the cavity. 
     The first key may extend into the annular trough when the piston is actuated. 
     A recess may be provided in the annular trough, and the first key may be configured to extend into the recess. 
     A side wall of the first key and a side wall of the recess may be disposed to engage each other and to communicate torque from the first coupler to the second coupler sufficient to cause the first coupler to rotate the second coupler about its longitudinal rotational axis. 
     The first coupler may further comprise a second key and a third key, and the first key, the second key and the third key may be spaced equiangularly about the longitudinal rotational axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of an agricultural harvester and agricultural harvesting head incorporating the present invention. 
         FIG. 2A  is a cross-sectional view of an extendable driveshaft and coupler that connect the agricultural harvester and agricultural harvesting head of  FIG. 1  taken at section line  2 - 2  in  FIG. 1 . 
         FIG. 2B  is a detail cross-sectional view of the extendable driveshaft arrangement in the foregoing figures. 
         FIG. 3  is a cross-sectional view of the coupler of the foregoing figures taken at section line  3 - 3  in  FIG. 1 . 
         FIGS. 4A-4F  are cross-sectional views of the extendable driveshaft and coupler of the foregoing figures at various stages of the engagement and disengagement process. 
         FIG. 5  is a control system configured to operate the arrangement of  FIGS. 1-4F . 
     
    
    
     DETAILED DESCRIPTION 
     In the disclosure herein, the terms “front”, “forward”, “in front of” and the like refer to a forward direction of travel “V” indicated in  FIG. 1 . The forward direction of travel is a direction traveled by the agricultural harvester  100  when it is moving in a straight line harvesting crops. The terms “rear”, “backward”, “behind”, “to the rear of”, and the like refer to the direction opposite to the forward direction of travel “V”. The term “lateral”, “width”, or “side-to-side”, refer to a direction perpendicular to the forward direction of travel “V”. 
     In  FIG. 1 , an agricultural harvester  100  comprises a self-propelled vehicle  102  from which a feederhouse  104  extends from the forward end of the self-propelled vehicle  102 . The agricultural harvester  100  supports an agricultural harvesting head  106 , which is supported on the forward free end of feederhouse  104 . An enclosed operator station  105  is disposed on the self-propelled vehicle  102  above the feederhouse  104 . The agricultural harvesting head  106  further comprises a frame  107  that is elongate and extends substantially the entire width of the agricultural harvesting head  106 . 
     In normal operation, the agricultural harvester  100  is driven through the field in a forward direction of travel “V”. As the agricultural harvester  100  travels, it carries the agricultural harvesting head  106  with it. 
     A reciprocating knife  108  disposed at the front of the agricultural harvesting head  106  and is supported on the frame  107 . The reciprocating knife  108  extends substantially the entire lateral width of the agricultural harvesting head  106 . The reciprocating knife  108  severs crop plants near their roots, and they fall upon the laterally extending conveyors (not shown) of the agricultural harvesting head  106 . They are then conveyed toward the center of the agricultural harvesting head  106  by conveyors, and are then sent rearward through a conveyor (not shown) that is disposed inside the feederhouse  104  and into the self-propelled vehicle  102  itself. Once in the self-propelled vehicle  102 , the severed crop plants are further processed by separating grain from material other than grain (MOG) and saving the grain in a grain tank  110 . Periodically, a vehicle travels alongside the self-propelled vehicle  102  and receives grain from the grain tank  110  which is carried outward away from the vehicle through a conveyor  112 . In  FIG. 1 , the conveyor  112  is shown in its storage position. During unloading operations, however, the conveyor  112  is pivoted to extend laterally away from the side of the self-propelled vehicle  102 . 
     The various moving devices in the agricultural harvesting head  106  are driven by the engine in the self-propelled vehicle  102 . The engine in the self-propelled vehicle  102  transmits power to a driveshaft  114  that is disposed at and supported on the front of the feederhouse  104 , causing the driveshaft  114  rotate. 
     A first coupler  116  is fixed to one end of the driveshaft  114 . The first coupler  116  is configured to mate with and drivingly engage a second coupler  118 . The second coupler  118  is fixed to a second driveshaft  120 . 
     When the first coupler  116  and the second coupler  118  are drivingly engaged, the engine transmits power to the driveshaft  114 , through the first coupler  116 , into the second coupler  118 , and then into the second driveshaft  120 . 
     Second driveshaft  120  extends across the rear of the agricultural harvesting head  106  to the left end of the agricultural harvesting head  106  where it enters a first gearbox  122 . A third driveshaft  124  is coupled to the second driveshaft  120  and is driven thereby. Third driveshaft  124  extends forward adjacent to the left end of the agricultural harvesting head  106  and is coupled at its forward end to a second gearbox  126 . Second gearbox  126 , in turn, is coupled to and drives the reciprocating knife  108 , the left side conveyor  128 , the right side conveyor  130 , the center conveyor  132 , and other. 
     In  FIG. 2 , driveshaft  114 , first coupler  116 , and second coupler  118  are shown in the same spaced apart arrangement as they are shown in  FIG. 1 . Driveshaft  114  can be extended and retracted by the selective injection and removal of hydraulic fluid from first hydraulic fluid connector  200 . Driveshaft  114  has a first sliding shaft  202  and a second sliding shaft  204  that are engaged each other to permit sliding relative movement of the first sliding shaft  202  with respect to the second sliding shaft  204 . The first sliding shaft  202  and the second sliding shaft  204  have a mating surface features that permit them to slide with respect to each other in a direction parallel to the longitudinal axes, yet permit them to communicate torque, and thus power one to the other. The mating surface features include splines  206  on the outer surface of first sliding shaft  202 , and splines  208  disposed on an inner surface of second sliding shaft  204 . Splines  206  and splines  208  are the structures that mutually interengage with each other to permit first sliding shaft  202  to slide with respect to second sliding shaft  204  while simultaneously permitting torque to be communicated from first sliding shaft  202  to second sliding shaft  204 . 
     First sliding shaft  202  is disposed within second sliding shaft  204 . First sliding shaft  202  has a hollow bore that receives a piston  210  that is supported on a piston rod  212 . Piston rod  212  is fixed to the outer end  214  of second sliding shaft  204 . 
     The first hydraulic fluid connector  200  is supported for rotation on the outer surface of first sliding shaft  202 . First hydraulic fluid connector  200  comprises a connector body  216  that is generally cylindrical, a first hydraulic connector  218 , a second hydraulic connector  220 , a first shaft seal  222 , a second shaft seal  224 , and a third shaft seal  226  that is disposed between the first hydraulic connector  218  and the second hydraulic connector  220  in an axial direction. The first shaft seal  222  and the second shaft seal  224  are disposed at each end of the first hydraulic fluid connector  200  to prevent hydraulic fluid injected into the first hydraulic fluid connector  200  from leaking out between the first hydraulic fluid connector  200  and the outer surface of first sliding shaft  202 . The third shaft seal  226  is disposed between the first hydraulic connector  218  and the second hydraulic connector  220  to prevent hydraulic fluid from passing directly from the first hydraulic connector  218  to the second hydraulic connector  220  (and vice versa) without first passing through the longitudinal bore  228  of the first sliding shaft  202  and effecting movement of the piston  210  and piston rod  212  disposed inside the longitudinal bore  228 . 
     In operation, the first hydraulic fluid connector  200  can turn freely around the outer surface of the first sliding shaft  202  upon the first shaft seal  222 , the second shaft seal  224 , and the third hydraulic seal. The first sliding shaft  202  can rotate about its longitudinal axis, and communicate power from the driveshaft  114  to the second driveshaft  120  and the first hydraulic fluid connector  200  can be held stationary. 
     This is particularly beneficial because it permits the first hydraulic fluid connector  200  to be connected to stationary hydraulic lines, and held in place to extend and retract the driveshaft  114  as the driveshaft  114  is rotating. 
     First hydraulic connector  218  and second hydraulic connector  220  are connected to hydraulic lines to communicate hydraulic fluid to and from the first hydraulic fluid connector  200 . The hydraulic lines, hydraulic valves, electronic controls that are used to direct hydraulic fluid into and out of the first hydraulic fluid connector  200  form no part of this invention. They are of conventional arrangement and are well known in the art. 
     When hydraulic fluid is injected into the second hydraulic connector  220 , the hydraulic fluid passes into an annular gap  229  that is disposed between an inner surface of the connector body  216  and an outer surface of the first sliding shaft  202 . The first hydraulic passageway  230  is disposed to conduct hydraulic fluid from the annular gap  229 , through the outer surface of the first sliding shaft  202  and thence to the right side (in  FIGS. 2A ,  2 B) of the piston  210 . This hydraulic fluid causes the piston  210  to move to the left (in  FIGS. 2A ,  2 B) in the longitudinal bore  228 . As the piston  210  moves to the left, hydraulic fluid in the longitudinal bore  228  on the left side of the piston  210  is forced into a second hydraulic passageway  232  in the piston rod  212 . Hydraulic fluid entering the second hydraulic passageway  232  travels to the right end (in  FIGS. 2A ,  2 B) of the piston rod  212  where it is released and returns back to the first hydraulic fluid connector  200  traveling around the outer annular surface of the piston rod  212 . Upon arriving back at the first hydraulic fluid connector  200 , the hydraulic fluid meets a fourth shaft seal  234 , which seals the outer surface of piston rod  212  against the inner surface of longitudinal bore  228 . Fourth shaft seal  234  prevents the returning hydraulic fluid from acting upon the right face of the piston rod  212  and forces it to exit the first sliding shaft  202  through third hydraulic passageway  236 . Fluid exiting the first sliding shaft  202  enters an annular gap  237  that extends about the periphery of the first sliding shaft  202 . Fluid entering the annular gap  237  enters the first hydraulic connector  218  and is carried away from the first hydraulic fluid connector  200 . The annular gap  229  and the annular gap  237  permit hydraulic fluid to be communicated to and from the first hydraulic fluid connector  200  to the first sliding shaft  202  regardless of the rotational position of the first hydraulic fluid connector  200  with respect to the first sliding shaft  202 . 
     Thus, hydraulic fluid injected into second hydraulic connector  220  causes driveshaft  114  to extend. Similarly, injecting fluid into first hydraulic connector  218  causes driveshaft  114  to retract. 
     Referring now to  FIG. 4A , a second hydraulic fluid connector  400  is provided on driveshaft  114  to communicate hydraulic fluid to and from the first coupler  116 , causing the first coupler  116  to drivingly engage the second coupler  118 . The second hydraulic fluid connector  400  comprises a second connector body  402  that is generally cylindrical, a third hydraulic connector  404 , a fifth shaft seal  406 , a sixth shaft seal  408  and a bearing  410 . 
     The second hydraulic fluid connector  400  is supported on the bearing  410  on second sliding shaft  204 . This support permits it to rotate with respect to the outer surface of the second sliding shaft  204 . As with the first hydraulic fluid connector  200 , this permits the second hydraulic fluid connector  400  to be held stationary as the driveshaft  114  (and hence the second sliding shaft  204 ) rotate about its longitudinal axis. As with the first hydraulic fluid connector  200 , this permits hydraulic lines to be connected to the third hydraulic connector  404 , and fluid to be introduced into or extracted from the third hydraulic connector  404  while the driveshaft  114  is rotating. 
     Fifth shaft seal  406  is located on the right side (in  FIGS. 4A-4F ) and extends between the inner surface of the second hydraulic fluid connector  400  and the outer surface of second sliding shaft  204 . Fifth shaft seal  406  prevents hydraulic fluid from leaking out of the second hydraulic fluid connector  400  along the outer surface of second sliding shaft  204 . 
     Sixth shaft seal  408  is located on the left side (in  FIGS. 4A-4F ) and extends between the inner surface of the second hydraulic fluid connector  400  and the outer surface of the second sliding shaft  204 . Sixth shaft seal  408  prevents hydraulic fluid from leaking out of the second hydraulic fluid connector  400  along the outer surface of second sliding shaft  204 . 
     Second sliding shaft  204  has a fourth hydraulic passageway  412  that conducts hydraulic fluid from an outer surface of second sliding shaft  204  to an inner chamber  414 . Inner chamber  414  supports a piston  416  for axial movement with respect to a longitudinal axis of driveshaft  114 . Piston  416  seals against the inner surface of inner chamber  414 , and is actuated by hydraulic fluid that is injected into or extracted from third hydraulic connector  404 . Hydraulic fluid is conducted from the third hydraulic connector  404  into an annular gap  417  extends about the outer surface of second sliding shaft  204 . Hydraulic fluid in the annular gap  417  is conducted into the fourth hydraulic passageway  412 , and thence into the inner chamber  414 . 
     By providing the annular gap  417 , hydraulic fluid may be conducted from the third hydraulic connector  404  to the piston  416  to actuate the piston regardless of the rotational position of the second hydraulic fluid connector  400  with respect to the second sliding shaft  204 . 
     In operation, hydraulic fluid from outside sources is injected into the third hydraulic connector  404 . This hydraulic fluid travels through the fourth hydraulic passageway  412  and into the inner chamber  414 . Once in the inner chamber  414 , the hydraulic fluid acts against the face of the piston  416 . This causes the piston  416  to move axially with respect to the driveshaft  114  (i.e. the second sliding shaft  204 ). I this movement of the piston  416  causes a coil spring  418  to push against the piston  416  and be compressed. 
     When hydraulic fluid is released from the third hydraulic connector  404 , the coil spring  418  releases its stored internal energy, and pushes the piston  416  to the right (in  FIGS. 4A-4F ) with respect to the driveshaft  114  (the second sliding shaft  204 ). This causes the hydraulic fluid in the inner chamber  414  to be ejected from the third hydraulic connector  404 . 
     The piston  416  is a portion of the first coupler  116 , which is fixed to the outer end of the driveshaft  114  (the second sliding shaft  204 ). 
     The first coupler  116  comprises a coupler body  420  that is fixed to a flange  422  with threaded fasteners  424 . Flange  422  extends outward from the leftmost end of the second sliding shaft  204  and provides a mounting point for the coupler body  420 . 
     The coupler body  420  encloses the piston  416 , as well as a conical member  426  that abuts the piston  416  and is actuated by the piston  416  when the piston  416  moves axially. 
     Referring to  FIG. 3 , the coupler body  420  has three slots  300  that are equiangularly disposed with respect to each other in a plane perpendicular to the longitudinal axis of first coupler  116  and the longitudinal axis of driveshaft  114 . Each of the three circumferential slots  300  receives and supports a corresponding one of keys  302 . Each of the three circumferential slots  300  supports its corresponding key  302  for radial movement toward and away from a longitudinal rotational axis  434  of second coupler  118 , which is coaxial with the driveshaft  114 , the first sliding shaft  202 , and the second sliding shaft  204 . 
     Referring back to  FIGS. 4A-4F , as hydraulic fluid from an outside source is injected into the third hydraulic connector  404 , it causes the piston  416  to translate to the left (in  FIGS. 4A-4F ). This movement causes the conical member  426  to also translate to the left with respect to the coupler body  420 . The conical member  426  has an outer conical surface  428  that abuts an inner surface of each of the three keys  302 . The three keys  302  are constrained by the sidewalls of their respective three circumferential slots  300  such that the movement of the conical member  426  to the left causes the three keys  302  to move radially outward with respect to the coupler body  420 . 
     Thus, by introducing hydraulic fluid into the third hydraulic connector  404 , the three keys  302  of the first coupler  116  extend outward from the coupler body  420 . Similarly, by permitting hydraulic fluid to escape from the third hydraulic connector  404 , the three keys  302  of the first coupler  116  retract inward into the coupler body  420 . 
     The second coupler  118  has a coupler body  429  that is generally cylindrical and defines a cavity  430 . The cavity  430  is generally cylindrical, and has a longitudinal axis that is parallel to the longitudinal rotational axis  434 . The opening of the cavity  430  is defined by an opening in an end of the second coupler  118  that is opposite the second driveshaft  120 . The opening of the cavity  430  faces the first coupler  116 . 
     The internal walls of the second coupler  118  that define the cavity  430  are configured to receive and support the outer end of the first coupler  116 , which includes the three keys  302 . 
     The internal walls of the second coupler  118  that define the cavity  430  define a shoulder  432  in the form of an annulus that extends inwardly toward the longitudinal rotational axis  434  of the second coupler  118 . 
     The shoulder  432  extends around substantially the entire inner circumference of the cavity  430 , such that it defines a trough  436  in the form of an annulus. Trough  436  is disposed in the cylindrical side wall of cavity  430 . Trough  436  is coaxial with the longitudinal rotational axis  434  and coaxial with the second driveshaft  120 . 
     Six recesses  438  are formed in the internal walls of the second coupler  118  that define the cavity  430 . The six recesses  438  are disposed at the bottom of the trough  436 . The six recesses  438  have a longitudinal extent that is generally parallel to the longitudinal rotational axis  434 . The longitudinal extent of the recesses  438  is greater than the width of the recesses  438 . 
     The recesses  438  are equiangularly spaced about the longitudinal rotational axis  434  as measured in a plane that is normal to the longitudinal rotational axis  434 . Each of the recesses  438  is disposed to engage an outer end portion  440  of a corresponding key  302 . 
     Torque about the longitudinal rotational axis  434  is communicated from the first coupler  116  to the second coupler  118  through the keys  302  that extend into the recesses  438 . 
       FIG. 4A  shows the two couplers in a starting position in which the first coupler  116  and the second coupler  118  are not engaged with the each other. In a first step of a coupling process, hydraulic fluid is introduced into the second hydraulic connector  220  of the first hydraulic fluid connector  200  and is communicated into the longitudinal bore  228 . 
     As hydraulic fluid fills the longitudinal bore  228 , the hydraulic fluid pushes the piston  210  to the left (in  FIG. 2A ) causing driveshaft  114  to extend in length. 
     Eventually, each of the three keys  302  will contact an outer edge of the shoulder  432 . This relationship is illustrated in  FIG. 4  B. As hydraulic fluid continues to fill the longitudinal bore  228 , and driveshaft  114  continues to extend, the outer wall  442  of the trough  436  will push against the three keys  302 , causing them to slide inwardly in their respective circumferential slots  300 , and translate radially inward toward the longitudinal rotational axis of the first coupler  116 . 
     Continued filling of hydraulic fluid into the longitudinal bore  228  will eventually cause the three keys  302  to overtop the shoulder  432  and slide further into the second coupler  118  without further radial translation. This is shown in  FIG. 4C . 
     Eventually, continued hydraulic fluid filling of the longitudinal bore  228  will cause the three keys  302  to pass the shoulder  432  and be received into the trough  436 . 
     An end surface  444  of the first coupler  116  will engage an inner surface  446  of the cavity  430 , preventing further movement of the first coupler  116  into the second coupler  118 . 
     The three keys  302  at this point are in the retracted positions and oriented radially inwardly of the trough  436 . 
     Hydraulic fluid is then applied to the third hydraulic connector  404 . Hydraulic fluid flowing into the first coupler  116  causes the three keys  302  to extend outwardly and away from the rotational axis of the first coupler  116  until the three keys  302  abut the bottom of the trough. This position is shown in  FIG. 4D . 
     The three keys  302  extend further, however, when they are aligned with three of the six recesses  438  that are formed in the bottom of the trough  436 . To be received into a corresponding three of the six recesses  438 , the first coupler  116  must be rotationally aligned with respect to the second coupler  118 , such that the three keys  302  are directly above three corresponding recesses of the six recesses  438 . 
     In order to do this, the operator engages the engine to driveshaft  114  and begins to gently rotate driveshaft  114 . The first coupler  116  is fixed to the end of driveshaft  114 , and therefore rotates with the driveshaft  114 . 
     Eventually, the first coupler  116  rotates within the second coupler  118  until the three keys  302  are aligned with three corresponding recesses of the six recesses  438 . When this happens, the hydraulic pressure provided by fluid introduced into the third hydraulic connector  404  causes the outer end portions  440  of the three keys  302  to extend further from the rotational axis of the first coupler  116  and drop into three corresponding recesses of the six recesses  438 . 
     When the three keys  302  drop into three corresponding recesses of the six recesses  438 , the circumferentially facing sidewalls  448  of the three corresponding recesses of the six recesses  438  abut the circumferentially facing sidewalls  450  of the three keys  302 . These abutting sidewalls communicate torque. From that moment, the first coupler  116  and the second coupler  118  are locked together as a single unit. 
     As long as hydraulic fluid is not released from the third hydraulic connector  404 , the three keys  302  stay extended. The first coupler  116  cannot be pulled out of the second coupler  118  because the surfaces of the three keys  302  will abut the shoulder  432 . Similarly, any rotation of the first coupler  116  will be communicated to the second coupler  118  because of the abutting relationship of the three keys  302  against the side walls of the three corresponding recesses of the six recesses  438 . 
     In order to ensure that the first coupler  116  and the second coupler  118  are properly oriented when this engagement process occurs, both the first coupler  116  and the second coupler  118  should be held in a predetermined alignment one with respect to the other when the operator, who is driving the self-propelled vehicle  102  from the operator station  105 , drives a self-propelled vehicle  102  forward and inserts the feederhouse  104  into an aperture on the back of the agricultural harvesting head  106 , then raises the feederhouse  104  until agricultural harvesting head  106  is raised and substantially or totally supported on a head support  452 . 
     Head support  452  is typically in the form of one or more hooks that extend forward and upward from the front of the feederhouse  104 . These hooks are received in an aperture or apertures in the back of the agricultural harvesting head  106 . 
     When the operator lifts the feederhouse  104  into the air using feederhouse lift cylinders (not shown) the agricultural harvesting head  106  is supported in its proper position on the feederhouse  104 . In this position, the first coupler  116  and the second coupler  118  are substantially coaxial, such that when the driveshaft  114  is extended, the first coupler  116  will be properly received into the second coupler  118 . 
     To ensure that the second coupler  118  is in the appropriate position when the operator has raised the feederhouse  104  into the air and lifted the agricultural harvesting head  106  into its proper orientation with respect to the feederhouse  104 , a coupler support  454  is provided that extends from the agricultural harvesting head  106 . The coupler support  454  is positioned on the agricultural harvesting head  106  such that it supports the second coupler  118  in its proper alignment with respect to the first coupler  116 . 
     The coupler support  454  can comprise brackets, straps, bolts, cradles, detents, or other devices having surfaces to hold the second coupler  118  in proper alignment. In one arrangement, the coupler support  454  includes several spring-loaded ball detents that engage corresponding recesses in the second coupler  118 . In another arrangement, the coupler support  454  is a cradle extending underneath the second coupler  118  to hold it in proper alignment. 
     The first coupler  116  and the second coupler  118  may be provided with a range of movement to accommodate pivoting in flexing of the agricultural harvesting head  106  on the feederhouse  104 . In one common arrangement, an agricultural harvesting head  106  can be tilted side to side with respect to the feederhouse  104  and the self-propelled vehicle  102  in order to better follow ground terrain and harvest crops. 
     This arrangement, however, means that the driveshaft  114  and the second driveshaft  120  must be free to move up and down with respect to the agricultural harvesting head  106  as the agricultural harvester  100  travels through the field harvesting crop. 
     To provide this freedom of movement during normal operation, the operator performs an additional step as part of the coupler engagement process described above. Once the operator has engaged the two couplers together to communicate torque and prevent them from being pulled apart, he couples a source of hydraulic fluid under pressure to the first hydraulic connector  218 . As described above, this causes the driveshaft  114  to retract and its overall length to be reduced. As the length of the driveshaft  114  is reduced, the driveshaft  114  pulls the first coupler  116  and the second coupler  118  (which are bound together at this point) to the right (in  FIG. 2A ), and pulls the second coupler  118  out of its coupler support  454 . The coupler support  454  will be moved relatively with respect to the second coupler  118  to the position shown in dashed lines in  FIG. 2A  the second coupler  118  is no longer contacting the coupler support  454 , and a clearance “C” (in  FIG. 2A ) is generated between the bottom of second driveshaft  120  and the coupler support  454 . 
     The second coupler  118  can translate without being disengaged from the second driveshaft  120  because the second driveshaft  120  has a splined section  456  defined by an inner tube  458  and an outer that is received inside an outer tube  460 . The splined section  456  is dimensioned such that when the second coupler  118  is withdrawn from the coupler support  454  and clearance “C” is provided, there is still sufficient engagement between the inner tube  458  and the outer tube  460  of the second driveshaft  120  that power can be communicated from the driveshaft  114  to the first gearbox  122 , and thence to the reciprocating knife  108  and the other driven elements on the agricultural harvesting head  106 . 
     A flexible joint  462  is provided along the length of the second driveshaft  120 . This flexible joint  462  permits the agricultural harvesting head  106  to pivot with respect to the feederhouse  104 . The flexible joint  462  comprises, for example, a universal joint or constant velocity joint. 
     Referring to  FIG. 5 , a control system  500  for controlling the arrangement of  FIGS. 1-4F  is illustrated. Control system  500  comprises an operator input device  502 , an electronic control unit (ECU)  504 , a first valve  506 , a hydraulic fluid source  508 , a hydraulic fluid reservoir  510 , and a second valve  512 . 
     The operator input device  502  may be a stick, lever, button, dial, knob, shaft encoder, keyboard, touch screen, voice-recognition system, or other electronic operator input device capable of indicating to ECU  504  that the operator desires an engagement or disengagement of driveshaft  114  to second driveshaft  120 . In one arrangement, the operator input device  502  is located in the cab of the agricultural harvester  100  (see  FIG. 1 ). In an alternative arrangement, the operator input device  502  is located on or adjacent to the feederhouse  104  where the operator can engage and disengage the driveshaft  114  to the second driveshaft  120  while observing the engagement process and the disengagement process. 
     The ECU  504  is connected to the operator input device  502  to receive a signal indicating the operator&#39;s desire to engage or disengage driveshaft  114  to second driveshaft  120 . 
     The first valve  506  is coupled to the hydraulic fluid source  508  to receive fluid therefrom, and to control the flow of hydraulic fluid to and from the second hydraulic fluid connector  400 . The first valve  506  is coupled to the hydraulic fluid reservoir  510  to return hydraulic fluid from the second hydraulic fluid connector  400  to the hydraulic fluid reservoir  510 . The ECU  504  is coupled to the first valve  506  to actuate the first valve  506 . The first valve  506  is connected to the third hydraulic connector  404 . 
     The second valve  512  is coupled to the hydraulic fluid source  508  to receive fluid therefrom, and to control the flow of hydraulic fluid to and from the first hydraulic fluid connector  200 . The second valve  512  is coupled to the hydraulic fluid reservoir  510  to return hydraulic fluid from the first hydraulic fluid connector  200  to the hydraulic fluid reservoir  510 . The ECU  504  is coupled to the second valve  512  to actuate the second valve  512 . The two hydraulic fluid conduits extending from the second valve  512  are connected to the first hydraulic connector  218  and the second hydraulic connector  220 . 
     In a first mode of operation, when the driveshaft  114  and the second driveshaft  120  are disengaged, the ECU  504  is programmed to monitor the state of the operator input device  502 , and when the operator input device  502  is actuated, to actuate the second valve  512  to extend the driveshaft  114  so that the first coupler  116  engages the second coupler  118 . 
     The ECU  504  is programmed to then actuate the first valve  506  to extend the keys  302  until they engage the second coupler  118 . 
     The ECU  504  is programmed to then rotate the driveshaft  114  for a portion of a turn until the keys  302  until the three keys  302  are aligned with three corresponding recesses  438  of the six recesses  438 . The hydraulic pressure acting against the piston  416  (the hydraulic pressure being provided by first valve  506 ) will cause the keys  302  to extend into the three corresponding recesses  438 . 
     The ECU is programmed to then actuate the second valve  512  and retract the driveshaft  114 . This causes the first coupler  116  and the now-engaged second coupler  118  to move rightward (in  FIGS. 4A-4F  and  FIG. 5 ) until the second coupler is pulled away from coupler support  454 . At this point, the driveshaft  114  and the second driveshaft  120  are coupled together and the operator can use his operational controls (not shown) in the traditional manner to drive the agricultural harvesting head  106  and harvest the field. 
     In a second mode of operation, when the driveshaft  114  and the second driveshaft  120  are engaged, the ECU  504  is programmed to monitor the state of the operator input device  502 , and when the operator input device  502  is actuated, to actuate the second valve  512  to extend the driveshaft  114  until the second coupler  118  is again supported by the coupler support  454 . 
     The ECU  504  is then programmed to actuate the first valve  506  to permit hydraulic fluid to flow from the second hydraulic fluid connector  400  to the hydraulic fluid reservoir  510  and the keys  302  to be responsively retracted into the coupler body  429 . 
     The ECU  504  is then programmed to actuate the second valve  512  to retract the driveshaft  114 , thereby separating the first coupler  116  from the second coupler  118  and leaving the second coupler  118  supported by the coupler support  454 . 
     In the arrangement described above, the ECU  504  performs these successive drive shaft engagement steps automatically. Alternatively, the ECU  504  can be programmed to respond to the operator input device  502  to perform each of the above steps sequentially as each step is sequentially commanded by the operator. Alternatively, the ECU can automatically perform two or more of the sequential steps above in sequence and wait for the operator to command the next sequential step using the operator input device  502 . 
     The description above and the figures herein are not intended to illustrate every possible way of constructing a device in accordance with the invention. The description and the figures merely illustrate the principles behind the invention and at least one way of constructing at least one device in accordance with the invention. The invention is defined by the claims below.