Abstract:
A rear door control mechanism for a stack-forming implement having a compressor roof first raises the door vertically to unlatch it and then rotates the door about an elevated and horizontally transverse axis to permit stack unloading. The door control mechanism functions independently of the compression roof and other wagons&#39; mechanical systems and assures positive door unlatching before the opening mechanism attempts to open the door.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a mobile hay stack-forming machine and more particularly to a control mechanism for opening and closing the door on such a machine. 
     It is old in the art for stack wagons having vertically reciprocable roofs to utilize the roof movement to unlatch and open and then close and latch their stack discharge doors. See, for example, the U.S. Pat. No. 3,901,142, granted Aug. 26, 1975 and assigned to Deere &amp; Company, wherein both latch movement and door movement are controlled by compressor roof movement. Other examples wherein latch movement is manually controlled and door movement is dependent upon roof movement are disclosed in U.S. Pat. No. 3,691,741 issued Sept. 19, 1972 to White et al., and U.S. Pat. No. 3,732,672 issued May 15, 1973 to Adee et al. 
     When a door latch must be manually released after a stack has been formed, the back pressure on the door exerted by the compressed stack often makes unlatching extremely difficult. When the unlatching control is integrally part of the door opening control, then failure of the latch to release can cause substantial damage to both the door and the crop-receiving body as the door opening control attempts to open a latched door. 
     An additional problem encountered with mechanical unlatching and door opening mechanisms similar to those available in the prior art arises as a result of the dust, dirt and foreign matter which accumulates in the springs, housing and channels of the mechanism. Manual unlatching and latching become difficult if not impossible unless this material is removed and unlatching even by mechanical means can be unreliable due to the compressed stack back pressure and foreign matter interference with latch clearances. 
     Accordingly, applicant has provided a door control mechansim which is neither manually unlatched nor latched, and is not dependently coupled with another operation of the stack wagon cycle. Neither does applicant&#39;s unlatching mechansim contain any channels, nor other dust and dirt gathering recesses which would fill with foreign matter to retard unlatching operation. In this manner, applicant has provided for positive opening of the latch prior to opening of the door and for opening of the door independently of roof position or movement. 
     SUMMARY OF THE INVENTION 
     In his application, applicant has disclosed a door opening mechanism which first raises the door vertically to unlatch the door, and then vertically swings and raises the door about a transverse axis to permit unloading of the formed stack. 
     It is therefore an object of the present invention to provide a door opening mechanism which positively unlatches before the door opening mechanism is engaged. 
     As part of this object, it is desired to provide a door opening mechanism which is unlatched without manual assistance. 
     To assure that unlatching does occur, it is another object to provide a door opening mechanism wherein the latch mechanism is simple and reliable and will not malfunction because of dust, dirt or foreign matter accumulations. 
     It is yet another object to provide a door opening mechanism which is mechanically operated and will open regardless of any back pressures which may be exerted on the door by the compressed crop material. 
     Yet another object is to provide a door opening mechanism which operates independently of the compressor roof or other stack wagon system and is therefore operatively dependable irrespective of the roof&#39;s position and other wagon systems. 
     Yet another object is to provide a door opening mechanism wherein the door will positively maintain any position of openness and not descend until so operated. 
     And yet another object of this invention is to provide a door control mechanism which is reliably operative by the operator from his cab, and is simple requiring only minimum maintenance. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a rear perspective view of a stack-forming machine embodying the invention thereon. 
     FIG. 2 is a side view of the door control mechanism when the door is in a latched and closed position. 
     FIG. 3 is a side elevation view similar to FIG. 2, but illustrating the door control mechanism when the door is in an unlatched and closed position. 
     FIG. 4 is a side elevation view similar to FIG. 2, but illustrating the door control mechanism when the door is in an opened position. 
     FIG. 5 is a schematic illustration of the hydraulic system for the compressor roof cylinders and the door control hydraulic cylinder illustrating the parallel hydraulic line configuration and the hydraulic system lock. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following description, right-hand and left-hand reference is determined by standing at the rear of the implement and facing the direction of travel. 
     Referring now to the drawings, there is disclosed in FIG. 1 a mobile stack-forming implement 10 having a main frame 12, a crop-receiving body 14 including an open end 16 through which a completed stack can pass, a vertically shiftable compressor roof 18 or canopy, and a door structure 20 including a door member for the open end. 
     The improved door control mechanism as illustrated includes means to both latch or unlatch and open and close the door member. 
     The latching or retaining means 22 includes a hooked latch member 24 pivotally attached to the lower portion of the door structure 20 and extending forwardly therefrom. A latch pin 26 extends out from the body 14 and is matingly engaged by the hooked latch member 24 to retain the door 28 in a closed position with the body 14. A biasing spring 30 is secured between the hooked latch member 24 and the door structure 20 to exert a downward force on the latch member 24 and retain it in an engaged position with the body pin 26. A stop, not shown, prevents the hooked latch member from rotating downwardly beyond a horizontal position. 
     The crop-receiving body 14 includes, adjacent its open end portion and on each side thereof, a vertically extending member 32. Supported at each end by the member 32 is a horizontal and transverse cross shaft 34. A lever means 36 or bell crank means is secured at the right end of the cross shaft 34 for vertical swinging movement about the cross shaft axis 38. This lever means 36, as illustrated on the current embodiment, includes a first lever arm 40 extending forwardly and second lever arms 42 and 44 extending rearwardly from the cross shaft axis 38. A powered means or hydraulic cylinder 46 has its base end secured with the crop-receiving body 14 and its rod end pivotally secured with the forward end of the lever means 36. Upon extension or retraction, the hydraulic cylinder 46 will swingably move the first lever arm 40 of the lever means through a vertical arc to rotate the cross shaft 34. 
     As illustrated, the invention utilizes a torque-transmitting pair of cross shaft sleeves 48 and 50, positioned exterior to and coaxial with the cross shaft 34. Each sleeve 48 and 50 is secured to the cross shaft at the shaft&#39;s 34 center portion only and extends from the cross shaft center portion transversely along the cross shaft 34 to the end portions of the shaft 34. One second lever arm 42 is secured to the right cross shaft sleeve 48 just inwardly of the first lever arm 40. An identical second lever arm 44 is secured to the outer end of the left cross shaft sleeve 50. As does the first lever arm 40, the second lever arms 42 and 44 extend from the cross shaft axis of rotation 38 for vertical swinging movement about the cross shaft transverse axis 38. 
     The second lever arms 42 ad 44 are of generally triangular shape and extend rearwardly from their respective cross shaft sleeves 48 and 50. Lateraly removed and rearwardly of the cross shaft axis 38 are pivotally supported on each second lever arm, a door lift member designated respectively 52 and 54. Each door lift member 52 and 54 is supported on the door 28 and extends rearwardly therefrom. 
     Each second lever arm 42 and 44 has a slotted opening 56 and 58 in the lower portion through which their respective door mounted pins 60 and 62 extend. This lost motion abutment means between the door structure 20 and lever means 36 is identified generally by the number 64. 
     The operation of the above-described door control mechanism is as follows. Upon completing a stack, the operator will open the hydraulic lock 66 (see FIG. 5), which has isolated the hydraulic system of the door control mechanism from the canopy lift hydraulic system and cylinders 68, and then activate the hydraulic fluid pump. FIG. 5 illustrates the two parallel hydraulic systems and the lock 66. As fluid flows to the powered means or hydraulic cylinder 46, the rod end will retract and swingably move the lever means 36, which includes the first lever arm 40 and second lever arms 42 and 44, through vertical arcs. 
     Unless a hydraulic cylinder were provided at each end of the cross shaft 34, unequal torque forces would be encountered at each end of the cross shaft 34 as the single hydraulic cylinder rotated the cross shaft to in turn rotate each second lever arm 42 and 44. To eliminate the necessity of providing a hydraulic cylinder on each side of the body 14, a torque transfer means utilizing center-connected cross shaft sleeves 48 and 50 is provided. As the single hydraulic cylinder 46 rod end thus rotates the first lever arm 40, the resulting rotational force is transferred to the cross shaft 34. With the sleeves 48 and 50 secured to the cross shaft 34 only at the shaft center portion, balanced torque forces are encountered in the shaft 34 and the sleeves 48 and 50 in turn transfer the torque forces outwardly along the sleeves and to each second lever arm 42 ad 44. In effect the first lever arm 40 and second lever arms 42 and 44 thus function as a bell crank means. 
     As the second lever arms 42 and 44 are rotated upwardly, the means pivotally interconnecting 70 the door structure and the lever arms 42 and 44 rotates about the cross shaft axis 38. Pivotally interconnected with each second lever arm 42 and 44 and forming part of the door structure are lift members respectively designated 52 and 54. As the second lever arms are rotated upwardly, the pivotal interconnections 70 and lift members 52 and 54 initially move in a generally linear and vertical path. During this portion of the lever means rotation the door 28 is lifted vertically to unlatch the latch means 22. As each second lever arm 42 and 44 is thus rotated, the slotted openings 56 and 58 will first move over the pins 60 and 62 and then continue along their respective upwardly swinging arcs to engageably contact their respective pins at the forward inside edge of each slotted openings 56 and 58. After the pins have abutted the forward inside edge of their respective slotted openings, the door 28 will be rotated about the cross shaft axis 38 as supported by the pivotal interconnecting means 70 and the lost motion connection means 64. When the hydraulic cylinder rod has fully retracted, the door 28 will be opened such that the completed stack can be removed. To assure that the door will remain in this opened position and not slowly descend during unloading, the hydraulic line lock 66 is activated. 
     After the stack is unloaded, the operator opens the lock and reverses the hydraulic line fluid flow. The hydraulic cylinder rod will extend causing the first lever arm 40 to rotate rearwardly permitting the door to lower. As the door closes against the open end of the body, the pins 60 and 62 in the slotted openings 56 and 58 will abut against the rearward walls of their respective slots 56 and 58. As the second lever arms 42 and 44 are rotated rearwardly further, the pressure exerted against the pins 60 and 62 by the rearward walls of the slots 56 and 58 will force the door forward against the crop-receiving body. In a reversed fashion, the door 28 will then be lowered vertically permitting the latch members 22 to be lowered onto the body mounted pins 26 to retain the door in a closed position.