Abstract:
An agricultural ram press has a bale chamber, a baling ram moveable in an oscillating manner in the bale chamber, a feed channel, a feed rake arranged in the feed channel and switchable between a gathering stroke motion which compresses crop in the feed channel and a filling stroke motion which moves the crop from the feed channel into the bale channel, and a drive for driving the feed rake and having a control rod interacting with an adjustable stop to control at least one of the motions of the feed rake.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2010 037 722.8 filed on Sep. 23, 2010. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d). 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an agricultural ram press with which crop picked up from a cultivated field is pressed into bale form. Such a ram press is known from EP 1 769 674 B1, for example. 
     This conventional ram press comprises a bale chamber in which a ram is driven in an oscillating manner in order to compress the crop conveyed into the bale chamber into a bale. The crop reaches the bale chamber via a pick-up device which gathers the crop from the cultivated field, and a feed channel in which a feed rake moves. The feed rake performs two motions, specifically a gathering stroke, in which the feed rake is adjacent to the entrance of the feed channel and enters it and then moves only through a front region of the feed channel in order to pull crop—that has been freshly conveyed into the feed channel—away from the entrance and precompress it in a rear region of the feed channel to create space at the entrance for subsequently arriving crop, and a filling stroke, in which the feed rake moves from the entrance to an exit, and which conveys the crop gathered and precompressed in the feed channel out of the feed channel and into the bale chamber. 
     The feed rake comprises a two-arm feed rake lever which has agitator tines—which enter the feed channel—on the end of a first arm; the end of the second arm is hinge-mounted to a feed rake coupling rod, and a pivoting point between the two arms makes a motion on a circular trajectory, driven by an eccentric. An end of the coupling rod facing away from the feed rake lever is hinge-mounted to a feed rake control rod. When the feed rake control rod is at rest while the pivoting point of the feed rake lever moves along its circular trajectory, the joint that connects the coupling rod to the second arm of the feed rake lever moves on a circular arc, and the agitator tines make gathering-stroke motions on an elliptical trajectory that is elongated in the horizontal direction. 
     To control a filling stroke, the feed rake control rod is coupled via a piston rod to the drive of the baling ram and undergoes a swivel motion which causes the agitator tines to follow a sickel-like path. 
     In the ideal case, the agitator tines should enter the entrance of the feed rake channel at a steep angle, in both a gathering stroke and a filling stroke, and then move with minimal clearance from the bottom of the channel in order to capture all of the crop in the feed rake channel. At the end of a feed rake stroke, the agitator tines should exit the channel at a steep angle, wherein the exit point should be selected such that a precompressed crop body remains in the feed channel, the length of which corresponds exactly to the height of the bale chamber, thereby enabling it to evenly fill the entire cross section of the bale chamber when it is conveyed into it using a filling stroke. In a filling stroke, however, the tines should continue following the base of the chamber to the exit thereof, and then exit. It is difficult to fulfill these requirements in a satisfactory manner using the conventional drive mechanism. Since the feed rake control rod is moved continuously during the filling stroke, the trajectories of the agitator tines can coincide during the filling stroke and the gathering stroke only at points, although exact conformity of the trajectories in a front region of the feed rake channel would be extremely practical. 
     SUMMARY OF THE INVENTION 
     The problem addressed by the invention is therefore that of creating a baler, the feed rake drive of which ensures a higher degree of freedom in terms of defining the trajectories of the feed rake motion. 
     The problem is solved in that, in the case of an agricultural ram press comprising a bale chamber in which a baling ram can move in an oscillating manner, a feed channel in which a feed rake can be switched between a gathering motion, with which crop is compressed in the feed channel, and a filling motion that moves the crop from the feed channel into the bale chamber, a drive of the feed rake comprises a control rod that interacts with an adjustable stop to control at least one of the motions of the feed rake. 
     The adjustable stop is preferably in the form of a rotatably drivable cam track. Since it is given a suitable shape, any correlation between a phase of the rotary motion of the cam track and the resulting deflection of the control rod can be implemented. 
     To minimize friction and wear, the control rod preferably carries a roller that impinges upon the cam track. 
     Rapid movement of the feed rake is desirable in order to quickly remove the crop, which is delivered continuously to the entrance of the feed channel, and precompress it in small portions, although the period of time in which the baling ram is moving can be much longer than that of the feed rake. If the frequency of the feed rake motion is n-fold the frequency of the ram motion, the cam track, which rotates at the frequency of the piston motion, can comprise n identical sectors in order to control n cycles of the feed rake motion per ram motion. 
     In a preferred embodiment, the motion of the feed rake in which the control rod interacts with the adjustable stop is the gathering stroke motion. 
     If the adjustable stop drives a motion of the control rod having the same period as the motion of the feed rake, then the path covered by the feed rake can be influenced arbitrarily via the course of this motion. 
     To force the control rod to follow a motion of the adjustable stop, the control rod preferably impinges upon the adjustable stop by way of an elastic element. 
     In order to guide the feed rake along a trajectory, at least in sections, during the filling motion stroke that differs from that of the gathering stroke motion, a coupling element can be provided that holds the control rod away from the stop at least during a portion of the filling stroke motion. 
     This coupling element is preferably a coupling rod which can be switched between an adjustable-length state in which it does not overcome the force of the elastic element, and a locked-length state in which it transfers a force to the control rod that is sufficient for overcoming the elastic element. 
     The coupling element can be driven by a drive shaft that also drives the baling ram. 
     Further features and advantages of the invention will become apparent from the description of embodiments that follows, with reference to the attached figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the ram press in a side view in accordance with the present invention; and 
         FIG. 2  shows a perspective view of the feed rake mechanism of the ram press in accordance with the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Ram press  1  shown in a schematic side view in  FIG. 1  is designed as a trailer to be coupled to a towing vehicle which is not depicted. It comprises a pick-up device  5 , which is also referred to as a pick-up, for picking up crop  6  from the ground. 
     The crop, which has been gathered by pick-up device  5  and fragmentized by a cutting device  10 , is conveyed to an entrance  11  of a feed channel  7 , the exit  16  of which leads into a bale chamber  2 . A baling ram  3 , which can move back and forth in bale chamber  2 , compresses the supplied crop, wherein compressed crop located further downstream in bale chamber  2 , and finished bales serve as an abutment for the compression. 
     Feed channel  7  extends in the shape of a curve between entrance  11  thereof and exit  16 , and is bounded by a concave base  8  and a cover  9 . Cover  9  comprises a plurality of longitudinal slots through which agitator tines can enter feed channel  7 . As shown in  FIG. 2 , agitator tines  13  are mounted on a crossmember  14  at regular intervals. Two feed rake levers  15  each comprise two arms  16 ,  17  which form an obtuse angle relative to one another and meet at an axle  39 . Lower arms  16  of the two feed rake levers  15  hold crossmember  14 . Axle  39  is driven by two feed rake cranks  40  on a circular path about an output shaft  41 . Output shaft  41  is coupled via a spur gearbox  42  to a main gearbox  4  which, in turn, is coupled via a universal drive shaft  22 , a bevel gear  21 , and a further universal drive shaft  20  to the towing vehicle which supplies it with drive energy. 
     The free end of upper arm  17  of each feed rake lever  15  is hinge-mounted via a feed rake coupling rod  37  to a control rod  36  which is disposed above bale chamber  2  and can pivot about an axis defined by a control shaft  35 . Control rod  36  is acted upon by a spring element, which is a gas strut  44  in this case, in the counterclockwise direction, and therefore a roller  43  carried by control rod  36  rests on the circumference of a cam track  45 . The circumference of cam track  45  comprises two identical sectors  50 , each of which extends across half of the circumference. It is coupled via a universal drive shaft  46  to main gearbox  4 . 
     In the depiction shown in  FIG. 1 , an output shaft  24  of main gearbox  4  is hidden behind a telescopic rod  29 , one end of which is hinge-mounted to control rod  36 , and the other end of which is hinge-mounted on a piston crank  25  driven by output shaft  24 . Piston crank  25  drives the back and forth motion of baling ram  3  via a connecting rod  26 . 
     Provided that telescopic rod  29  is not in a locked-length state, the motion of its end acting on piston crank  25  does not affect control rod  36 . The position thereof is therefore defined solely by the orientation of cam track  45 , against which roller  43  is pressed via gas strut  44 . Cam track  45  rotates at the same frequency as output shaft  24 , and so, over the course of one oscillation of baling ram  3 , roller  43  passes over the entire circumference of cam track  45 , thereby driving two oscillation cycles of control rod  36 . 
     Feed rake crank  40  also rotates at two-fold the frequency of piston  3 , i.e. feed rake crank  40  and cam track  45  rotate in a fixed phase relationship relative to one another. The orientation assumed by feed rake lever  15  in a certain phase of this motion depends on the contour of cam track  45 , which can be defined substantially arbitrarily. By defining this contour in a suitable manner, it is thereby possible to accurately monitor the shape of path  47  described by agitator tines  13  over the course of a gathering stroke. 
     An unambiguous rule for how to create the circumference of cam track  45  in order to guarantee an ideal course of path  47  cannot be given since this course depends both on the contour of cam track  45  and on the shape and the relative motion phases of other components of the feed rake mechanism, such as coupling rod  37 , feed rake lever  15 , and feed rake crank  40  in particular. However, it should be understood that, independent of the influences of these components, the shape of path  47  can be optimized via a suitable shape of cam track  45  since substantially no basic conditions need to be considered when defining the shape of cam track  45  except for the desired shape of path  47 . For example, the use of cam track  45  makes it possible in particular to attain a path shape in which the agitator tines enter entrance  11  of feed channel  7  substantially perpendicular to the longitudinal direction thereof, and the tips thereof then cover a long distance in the direct vicinity of base  17  be fore the motion abruptly changes direction and agitator tines  13  are withdrawn from feed channel  7 . 
     Given that the agitator tines enter entrance  11  at a steep angle, it is guaranteed that the supplied crop material is captured across substantially the entire cross section of feed channel  7  and is pushed into the feed channel. Given that agitator tines  13  move in the direct vicinity of base  8  in the direction of exit  16 , they prevent material from remaining uncompressed on base  8  and ensure that the crop body formed in the feed channel has a uniform density across the entire channel cross section. The contour of cam track  45  can also be used to define the point  47  of feed channel  7  at which agitator tines  13  exit, which, in turn, determines the dimensions of the precompressed crop body formed in a rear region of feed channel  7  on the other side of point  48 . It is therefore sufficient to change the shape of cam track  45  in order to vary the dimensions of the crop body and adapt it to the dimensions of bale chamber  2  such that a bale having a homogeneous density is obtained therein. 
     The number of gathering strokes required to preshape a crop body—which has the density required to be conveyed further into bale chamber  2 —in feed channel  7  is variable depending on the inflow of crop supplied by pick-up device  5 . To determine when a crop body is finished, a swivelable door  23  is disposed in the vicinity of exit  16 , against which the crop conveyed by the feed rake strokes backs up. If the pressure of the crop on door  23  exceeds a limit value, the crop body is finished, door  23  swivels to the side to expose the path into bale chamber  2 , and telescopic rod  29  is simultaneously locked in a position having a minimal length. As a result, when piston crank  25  subsequently rotates, telescopic rod  29  swivels control rod  36  against the force of gas strut  44  in the clockwise direction, thereby pulling roller  43  away from cam track  45 . As a result, feed rake lever  15  swivels in the clockwise direction about axle  39  which, in combination with the rotation of feed rake cranke  40 , causes agitator tines  13  to follow the course of base  8  along approximately the entire length thereof, as indicated by a path  49  in  FIG. 1 , before they exit feed channel  7  at the level of exit  16  after they have pushed the crop body into bale chamber  2 . 
     Sectors  50 , which form the circumference of cam track  45 , can each have a section that is shaped such that roller  43  remains in contact with the section even when telescopic rod  29  is length-locked. While roller  43  passes over this section, the path covered by agitator tines  13  is the same, regardless of whether a gathering stroke motion or a filling stroke motion is being performed at the moment. If this section is being passed over while agitator tines  13  are located in the front region of the feed channel, the path they cover in this front region is exactly the same in gathering strokes and filling strokes, and, since the shape of base  8  is adapted to this path, an excellent conveying effect can be ensured for both strokes. 
     It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. 
     While the invention has been illustrated and described as embodied in an agricultural ram press, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 
     What is claimed as new and desired to be protected by Letter Patent is set forth in the appended claims.