Abstract:
The cutter bar of a side-pull mower-conditioner is located within a housing including a forward top wall section defined by an access door that is hinged for being lifted from a substantially horizontal position to a raised position permitting access to the cutter bar. A towing tongue mounted at the side of the carrier frame of the mower-conditioner is mounted for swinging horizontally about a vertical axis and is operatively associated with the access door so that the open access door is closed when the tongue is swung toward the open door. In one embodiment, the association is a specially shaped door support member fixed to the tongue. In a second embodiment, the association is established by a linkage, and in a third embodiment, the association is through a hydraulic circuit, including a door cylinder coupled for moving the door between its open and closed position, coupled to the hydraulic tongue swing cylinder such that when the tongue swung cylinder is actuated for swinging the tongue toward the open access door, the access door is closed by the door cylinder prior to the operation of the tongue swing cylinder.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a side-pull mower-conditioner, and more specifically relates to a device for preventing an access door of the mower-conditioner, which has been inadvertently left open, from being damaged when the tongue swings across the zone occupied by the open door. 
   BACKGROUND OF THE INVENTION 
   The rotary cutter bar of many rotary mower conditioners are contained within a housing which includes a door comprising a rectangular panel which is disposed generally horizontally when closed, and a curtain coupled in depending relationship to a forward edge of the panel so as to extend vertically across the front of the machine. The curtain is pushed back by the standing crop, as the mower-conditioner advances, to allow the crop to be cut. The curtain provides shielding for the operator and bystanders from foreign objects which are engaged and propelled by the rotating cutting discs. The curtain and door assembly is typically hinged at the top of the housing so as permit the curtain and door assembly to be raised to allow better access for service of the cutter bar area of the machine. In some cases, this door and curtain assembly can be damaged by accidentally leaving the door open and effecting an operation which results in the tongue sweeping into the zone occupied by the open access door. 
   Some designs address the above-noted problem by designing the door such that by unhooking one end of the door support, the operator may pivot the door out about a vertical axis and then lay the door on the ground. This approach is used by the Vermeer Mfg. Co. on their Model 620 Mower-Conditioner and has the drawback that, once the servicing of the cutter bar is complete, the operator must pick the door up, pivot the door back into place and then fasten the door in place. 
   Other designs allow the tongue to pass over the door by mounting the tongue to the carrier frame at a height which results in the tongue structure being located higher than the opened door. This approach is used by Deere &amp; Company on the JD 946 and 956 Center Pivot Mower-Conditioners. The problem with this approach is that the high location of the tongue introduces higher forces into the carrier frame which must require heavier structure to compensate for them. 
   SUMMARY OF THE INVENTION 
   According to the present invention, there is provided an improved side-pull mower-conditioner which permits the tongue to be mounted at a relatively low location on the carrier frame without having to be concerned about damaging an open access door. 
   An object of the invention is to provide a side-pull mower-conditioner with a tongue which swings through a path which is occupied by the access door when the door is open, and to provide an operative association between the tongue and the door such that movement of the tongue toward the open door will cause the latter to close. 
   This object is achieved, in accordance with a first embodiment of the invention, by providing an operative connection between the tongue and the access door defined by a door engaging structure carried by the tongue and against which the door may rest when the door is opened, with the door engaging structure being shaped such that it causes the door to be moved from the path of movement of tongue in response to contact between the door engaging structure and the tongue caused by the tongue being swung toward the door. 
   The object is achieved, in accordance with a second embodiment of the invention, by providing an operative connection between the tongue and access door which is defined by a linkage coupled between the tongue and the door such that the linkage will close the door when the tongue moves toward the open door. 
   The object is achieved, in accordance with a third embodiment of the invention by providing an operative connection between the tongue and the access door which is defined by a hydraulic circuit including a hydraulic door cylinder coupled to the access door and coupled in circuit with the tongue swing cylinder such that, when a control valve for the tongue cylinder is actuated to swing the tongue toward the open access door, the door cylinder operates to close the access door prior to the swing cylinder operating to swing the tongue. 

   
     This and other objects will become apparent with a reading of the ensuing description together with the appended drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a left front perspective view of a side-pull mower-conditioner showing the tongue in an outward working position, showing the access door and associated safety curtain in a lowered working position and showing the tongue equipped with a door support structure, in accordance with a first embodiment of the invention. 
       FIG. 2  is a view like  FIG. 1 , but showing the access door in a raised open position wherein it rests against the door support structure. 
       FIG. 3  is an enlarged right rear perspective view of a portion of the structure shown in FIG.  2 . 
       FIG. 4  is a view similar to that of  FIG. 3  but showing a linkage connected between the tongue and the access door in accordance with a second embodiment of the invention. 
       FIG. 5  is a schematic representation of a third embodiment of the invention showing a hydraulic door-operating cylinder coupled to the door and to the hydraulic tongue swing cylinder in a hydraulic circuit. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1-3 , there is shown a side-pull mower-conditioner  10  including carrier or main frame  12  including a cross beam  14  extending transversely to a normal direction of travel and having opposite ends joined to depending wheel-support legs  16 . Wheel support arms  18  are respectively pivoted to lower ends of the legs  16  by pins  19 , with only the left-hand arm  18  being shown. Hydraulic wheel actuating cylinders  20  are coupled between brackets provided at upper rear locations of the legs  16  and rear ends of the wheel support arms  18 . Ground wheels  21  are mounted to the rear ends of the wheel support arms  18 . 
   The main frame  12  further includes a draft tongue support structure  22  which is joined to, and projects forwardly from, a leftward region of the cross beam  14 , however, the particular location of the tongue support structure on the beam  14  is not important to the present invention. A draft tongue  24  has a rear end coupled to a forward end of the support structure  22  by a vertical pin  26  which establishes an upright axis about which the tongue  24  may pivot horizontally. Coupled between the support structure  22  and the draft tongue  24  is an extensible and retractable hydraulic cylinder  28 , with the latter being shown in a fully retracted position wherein it positions the tongue  24  in a leftmost working position. It is to be noted that basic aspects of the present invention require only that the tongue  24  somehow be swung about the axis of the pin  26 . For example, in lieu of the cylinder  28 , any well-known remotely releasable coupling could be established between the tongue  24  and beam  14 , which when released permits the tongue  24  to pivot about the pin  26  by driving the towing tractor in an appropriate direction to effect swinging of the tongue in a desired direction. 
   A crop harvesting platform  30  includes a platform frame  32  including opposite side walls  34  joined by a rear frame structure  36 . The frame  32  is suspended from the carrier frame  12  by a three-bar linkage including a lower pair of links  38  and an upper link  40 . The lower pair of links  38  are respectively located at opposite sides of the platform  30  and have rear ends respectively pivotally coupled to the pair of wheel support arms  18 , and have front ends respectively pivotally coupled to lower rear locations of the platform frame structure  36 . A pair of counterbalance springs  42  have upper ends respectively coupled to upper front locations of the pair of legs  16  and have lower ends respectively coupled to lower rear locations of the platform frame member  36 . 
   Thus, it will be appreciated that the platform  30  may be moved between a lowered working position and a raised transport position through operation of the hydraulic cylinders  20  for adjusting the wheels  21  relative to the frame  12 . 
   The platform  30  includes a forward, generally horizontal top wall which extends between the opposite side walls  34 . The top wall includes a relatively narrow, fixed rear rectangular section  44  and a front rectangular section including a minor, fixed left-hand portion  48 , and a major right-hand portion forming an access door  50  that is mounted to a forward edge of the rear section  44  by a horizontal hinge assembly  52  that allows the door  50  to pivot vertically. Fixed to a forward edge of the access door  50  is a flexible shield  54  that hangs vertically in front of a rotary cutter bar (the cutter bar has been omitted from  FIG. 2  for the sake of simplicity) when the platform  30  is not in use. A flexible shield  56  is likewise mounted to a forward edge of the top wall left-hand minor portion  48 . Thus, it will be appreciated that when it is desired to gain access to the rotary cutter bar located within the enclosure defined by the top wall portion  50  and the flexible shield  54 , this may be done by pivoting the access door  50 , together with the flexible shield  54 , upwardly about the hinge assembly  52  from its operative position, shown in  FIG. 1 , to its open position, shown in FIG.  2 . 
   The present invention comes into play when the access door  50  is swung into its open position. Specifically, fixed to a lower right-hand surface location of a rear region of the tongue  24  is a triangular door engaging plate  60 . The door engaging plate  60  may be of any effective shape and is here shown as having a shape of a right triangle, with the hypotenuse being fixed along the tongue  24 , with the sides forming the right angle being located behind an upper left-hand corner of the access door  50 , and with an edge  62  of the plate  60  extending forwardly from the right angle and making an angle of about 30° with the tongue  24 . The edge  62  is engaged by, and supports the open access door  50  in a disposition where it is inclined gradually to the rear from the hinge assembly  48 . The edge  62  is so disposed relative to the access door  50 , that as the tongue  24  is swung toward the door, the door  50  is pivoted forwardly and closed before it is contacted by the tongue  24 . Therefore, if an operator should inadvertently leave the access door  50  in its open position and then resume an operation where it is desired to reposition the mower-conditioner  10  relative to the towing tractor by swinging the tongue  24  toward the open access door  50 , such an operation can be done without damaging the door  50  by engaging it with the tongue  24  since the door  50  will close before such an engagement occurs. While it is convenient in the disclosed embodiment for the door engaging plate  60  to be used to support the open access door  50 , it will be appreciated that the door  50  may be supported in its open position by other structure. 
   Referring now to  FIG. 4  there is shown an alternate embodiment where like structure is indicated by the same reference numerals given above. The only difference in structure is that instead of providing the tongue  24  with a door support plate, a linkage  66  is mounted between the tongue  24  and a central location of the access door  50 . Specifically, the linkage  66  includes a link  68  having a left-hand end pivotally mounted, as at an upright pin  70 , to a pair of vertically spaced ears  71  fixed to the tongue  24 . A bell-crank  72  is mounted to the rear section  44  of the top wall of the of the platform  30  for pivoting about an upright pin  74  located to the rear of a central location of the access door  50 . The bell-crank  72  includes a relatively short leg, which carries a swivel-eye  76  in which the link  68  is mounted for free sliding movement, the short leg being joined to, and making an angle of about 90° with, a relatively long leg which carries a roller  78  at its free end. As considered when the tongue  24  is in its left-most position and with the access door  50  open, as shown in  FIG. 4 , the short leg of the bell-crank  78  ends generally perpendicular to the door  50  while the long leg of the bell-crank extends generally parallel to the access door  50  with the roller  78  engaging the open access door  50 . An abutment  80 , which may be defined by a washer secured to the rod  68 , is positioned for engaging the swivel-eye  76  so as to cause the bell-crank  72  to pivot resulting in the roller  78  being swung forwardly a distance sufficient for closing the door  50  when the tongue  24  is swung toward the door. The length of the rod  68  which extends beyond the swivel-eye from the tongue ensures that the rod will remain within the swivel-eye  76  during operation with the door  50  in its closed operating position. The relative lengths of the short and long legs of bell-crank  72  ensures that sufficient motion will be imparted to access door  50  by the pivoting bell-crank  72  in response to movement of the tongue  24  for closing the access door  50  prior to the tongue reaching the door when swung toward it. For a simpler solution, the link  68  could be pivotally coupled directly to short leg of the bell-crank. This would result in the bell-crank  72  pivoting when the tongue  24  is swung subsequent to the door  50  being closed. 
   Referring now to  FIG. 5 , there is shown a schematic of a third embodiment of the invention. The difference between this embodiment and the second embodiment is that instead of connecting a linkage between the tongue  24  and the access door  50  to ensure that the latter is closed prior to being engaged and possibly damaged by the tongue when the door  50  is inadvertently left open and the tongue is swung toward the door, a hydraulic door closing cylinder  82  is mounted between respective central regions of the top wall section  44  and door  50 . The rod end of the cylinder  82  is coupled to the door  50  through the agency of a bracket  84  fixed to the door and containing, as considered when the access door  50  is closed, a fore-and-aft elongated, lost motion slot  86 , having a purpose explained below. The rod end of the cylinder  82  is equipped with a clevis that straddles the bracket  84  and is coupled to it by a pin  88  located in the lost motion slot  86 , with the pin  88  being located in the remote end of the slot  86  when the door  50  is open, as shown in the drawing. 
   For effecting operation of the door closing cylinder  82  in response to the tongue swing cylinder  28  being operated to swing the tongue  24  toward the open access door  50 , there is provided a hydraulic circuit  90  including a hydraulic pump  92  and sump  94  coupled to a four-way, three-position control valve  96  having a first port coupled by a first branched supply/return conduit  98  to respective rod ends of the tongue cylinder  28  and a door closing cylinder  82 . A second branched supply/return conduit  100  couples a second port of the control valve  96  to the head end of the door closing cylinder  82  and to a priority valve  102  including a first path to the head end of the tongue cylinder  28 , which is blocked in the direction of the cylinder  28  by a check valve  104 , and a second route to the head end of the cylinder  28 , which is normally blocked by a pressure-responsive valve  106 . 
   In operation, assuming that the access door  50  has been inadvertently left open and that the operator has resumed operation and desires to reposition the mower-conditioner  10  relative to the towing tractor, the valve  96  will be shifted upwardly from its neutral position shown in FIG.  5 . Pressure fluid will immediately be routed to the head end of the door closing cylinder  82  so as to pressurize the head end of the door cylinder  82  while the rod end is coupled to the sump  94 . No pressure fluid will at this time be routed to the tongue cylinder  28  since the pressure-responsive valve  106  of the sequencing valve  102  will block flow to the head end of the tongue swing cylinder  28 . The door  50  will close upon only a partial extension of the cylinder  82  taking place. When the cylinder  82  has become fully extended, the pressure in the conduit will rise and cause the pressure responsive valve  106  to shift to its open position. The tongue swing cylinder  28  will then extend to swing the tongue to the desired position whereupon the operator will return the control valve  96  to its neutral position. Thereafter, the valve  96  may be shifted to cause other desired movements of the tongue  24  with the door closing cylinder  82  extending or retracting without effecting the position of the closed access door  50  due to the lost motion slot  86 . Because the tongue swing cylinder  28  and the door closing cylinder  82  are coupled in parallel, and the resistance to movement offered by the door  50  is much less than the force required to swing the tongue  24 , it may be possible to eliminate the sequencing valve  102  since the cylinder  82  would normally extend prior to the cylinder  28  extending. 
   Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.