Abstract:
An improved means for controlling movement of the discharge door on an agricultural machine between its open and closed position, wherein the movement of associated machine parts is utilized to incur controlled movement of the discharge door.

Description:
This is a continuation of application Ser. No. 496,540, filed Aug. 12, 1974, and now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to stack-forming equipment and more particularly to a mobile stack-forming implement having a rear door with a mechanical means for controlling movement of the door operatively coupled with the implement&#39;s vertical reciprocal stack-forming compression means. 
     Stack-forming wagons having a vertical reciprocal roof for the container to assist in compressing the crop in the container are well known to the prior art. It is also well known to discharge the completed stack from the container body across the lowered rear door. Various mechanisms have been employed to open and then close the rear door after the stack has been unloaded. 
     SUMMARY OF THE INVENTION 
     The principle object of the present invention is to provide an improved rear door closing mechanism. More particularly, it is an object to operatively couple the stack-forming compression means with the rear door to utilize the compression means movement when closing the rear door. It is also an object to provide a mechanism that will control the descent rate of the rear door when it is opening. Yet another object is to provide a closing mechanism that is simple, requires few parts, is reliable in operation, inexpensive to manufacture and economical to maintain. 
     In pursuance of these and other objects, the invention includes a roof connected to bell cranks on the sides of the container that upon rocking causes the roof to raise or lower and a force-transmitting means or flexible cable interconnecting the rear door and one of the bell cranks, and a guide or sheave secured to the container side frame between the rear opening and said bell crank. 
     Through utilizing the movement of the bell crank, the door is opened and closed. As a hydraulic cylinder retracts to swing the bell cranks from the rearward to forward positions to lower the roof, the flexible cable is pulled forwardly around the sheave, causing the lowered door to be raised. As the door reaches a nearly closed position, the bell crank has nearly completed its cycle of movement, and the cable is in a slackened configuration. To eliminate the cable slack and thereby cause the door to close, a movable tightening or cable take-up means secured to said bell crank slidingly contacts the cable and lengthens the path followed by the cable. 
     To unload a completed stack, the compressor roof must be in a raised position. As the bell crank is rotated to raise the roof, the operator will unlatch the door and the bell crank&#39;s rotation can then be utilized to control the rate at which the attached cable lowers the rear door. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiment of the invention will be described in conjunction with the accompanying drawings in which: 
     FIG. 1 is a side view of a stack-forming implement with the door partially closed and the roof lift mechanism in its relative position. 
     FIG. 2 is an enlarged side view with portions broken away of a section of the cable and the bell crank. 
     FIG. 3 is a side view of the rear portion of the implement showing the door fully opened and the roof lift mechanism in its relative position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The stack-forming implement embodying the invention comprises, generally, a mobile frame adapted to be towed by a tractor, a crop-receiving container 10 carried by the frame and including a rear opening and door 12, a container top or roof 14 mounted for vertical reciprocal movement and operative to compress material in the container and a compressing mechanism for raising and lowering the container top 14. The compressing mechanism includes in part T-shaped bell cranks 16 and 18, pivotally mounted on the sides of the container and connected by links to the roof 16. The improved means for controlling door movement includes a flexible cable 20 interconnecting the rear door 12 and the rear T-shaped bell crank 16. 
     To the upper side portion of the rear door 12 is welded a transversely horizontal dowel-shaped rod 22. On the outer portion of the rod is a groove which circumscribes the entire rod circumference. Looped about the rod 22 and seated in the groove is the rearwardly portion of the flexible cable 20. Secured to the container frame forwardly of the door is a sheave 26. Swingably mounted on the container side for rotational movement about horizontally transverse axes are the compression mechanism T-shaped bell cranks 16 and 18. Attached to the lower surface of the rearward arm of the rear bell crank 16 is an arcuate part 28. The forward portion of the arcuate part 28 is secured by U-bolts 30, and the base of the L-shaped rearward portion of the arcuate part 28 is movably seated for up and down movement in an opening of the bell crank rear arm 32. 
     Welded to each side of the bottom of the forward arm 34 of the rearward bell crank 16 are brackets 36. Horizontally mounted between the brackets 36 is a transversely positioned pivotable rod 38. An adjustable eyebolt 40 extends through an opening in the rod 38 and a nut 42 is threaded on the eyebolt 40 forward end. 
     The cable 20 extends forwardly from the rear door dowel pin 22, around the sheave 26, slidingly contacts the arcuate part 28 mounted on the rear bell crank 16, and is secured to the loop of the eyebolt 40. A keeper spring 44 interconnects the cable loop adjoining the eyebolt 40 and the center bottom portion of the bell crank 16 and exerts an upwardly bias on the eyebolt 40. 
     The operation of the invention is as follows. When the stack has been completed, the compressor roof or top 14 is raised. As the operator activates the hydraulic cylinder 46 to rotate the bell cranks 16 and 18 to raise the compressor roof 14, the lower rear door 12 is opened through a latch mechanism described in detail in applicant&#39;s co-pending U.S. application Ser. No. 371,734 and not important for purposes herein. As the bell cranks 16 and 18 are rotated rearwardly, the cable 20 becomes slack. To prevent the rearward end of the eyebolt 40 from rotating downwardly about the pivotable shaft 38 as the bell crank 16 rotates rearwardly, and thereby jamming against the frame 48, the keeper spring 44 exerts an upwardly bias on the eyebolt 40 rearward end. As the roof 14 continues to raise, the door 12 is unlatched, and will then fall until the cable 20 contacts the arcuate part 28. The arcuate part 28 thus serves to cushion the fall of the door. The bell crank 16 swings through a fixed radius arc while the arcuate part 28 transcribes a different radius arc. Therefore the interaction of the arcuate part 28 with the cable 20 will diminish as the compressor roof 14 is raised and the arcuate part 28 swings away from the cable path. 
     After the stack is unloaded through the container rear opening and across the rear door 12, the operator need only lower the compressor top 14 to close the rear door. 
     As the hydraulic cylinder 46 retracts, the bell cranks 16 and 18 are rotated in a forwardly direction and the cable 20 is pulled forwardly. Since the linear distance of the arc swung by the bell crank 16 is less than the linear distance over which the rear door cable connection rod 22 travels to cause the door to close, slack in the cable will result after the bell crank 16 has been fully rotated and the compressor top 14 moved completely down. To eliminate that cable slack and thereby cause the door to close, the arcuate part 28 is secured to the bell crank 16 in a position wherein it would interact with the cable and lengthen the path the cable would follow. As the arcuate part 28 slidably interacts with the cable 20, the length of the path through which the cable 20 is moved by the bell crank 16 is increased. The slack is thereby taken up and the rear door closed and latched. Minor adjustments in cable 20 length are effected by advancing or unscrewing the nut 42 on the forward end of the eyebolt 40.