Abstract:
A round baler, including a front housing, a rear housing pivotally connected with the front housing by an upper axle secured in the front housing and supporting the rear housing for a pivotal movement relative to the front housing, and a locking device for latching the rear housing to the front housing in a closed operational position of the rear housing and releasable upon a pressure acting on the rear housing reaching a predetermined value, and including an element for latchingly connecting the rear housing with the front housing in a partially open position of the rear housing.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a round baler including a front housing, a rear housing pivotally connected with the front housing, an upper axle secured in the front housing and supporting the rear housing for a pivotal movement relative to the front housing, and locking means for latching the rear housing to the front housing in a closed operational position of the rear housing and releasable upon a pressure acting on the rear housing reaching a predetermined value. 
     2. Description of the Prior Art 
     German Publications DE 24 43 838A1 and DE 31 18 663A1 disclose mechanical locking devices for latching the front and rear housings. The rigid latching insures obtaining of high compression densities and uniform diameters of bales. In order to protect the drives of the compression elements and the compression elements themselves from overload, conventionally, a safety shear bolt, a friction clutch, or an automatically actuated cam decoupler is used in the main drive train of the baler. The actuation of a tying device is effected usually manually or automatically upon a predetermined pressure having been reached. The big drawback of balers equipped with the above-discussed over-load protection means consists in that when, upon shearing of the safety bolt, actuation of the friction or cam clutch, or upon sliding of the compression elements relative to a bale circumference, the bale remains, in particular at unfavorable crop conditions, in the compression chamber, the not yet tied bale cannot be set in rotation again without preliminary delatching the front and rear housings. Because of a large expansion force of the compressed material of the bale, the rear housing should be pivoted out by 30-50 cm. The large opening path of the rear housing results in that the bale has an overlarge diameter and cannot be tied up or can be tied up only partially. Practically, it means that it is necessary to compress the defective bale anew. 
     In a round baler produced by a firm Claas, type Rollant 66,46 silage 46 Roto Cut, pressure head 8/95, the front and rear housings are hydraulically latched. To protect the compression chamber from overload, a hydraulic overload protection device is provided which, upon the compression density exceeding a predetermined value, has its pressure limiting value actuated which results in bleeding of the oil off and in opening of the rear housing. The drawback of this type of protection consists in that the openings path of the rear housing is not limited, resulting in producing overlarge, not completely bound bales. There is no possibility of securing the rear housing in a closed position in which it would prevent an uncontrolled expansion of the bale. This is because the pressure limiting valve does not permit to obtain the necessary high closing pressure. 
     Accordingly, an object of the present invention is to provide a round baler which would insure finishing the formation of a bale, i.e., its tying up despite the stoppage of formation of the bale in the compression chamber, i.e., would insure tying of the bale and its ejection. 
     Another object of the present invention is to provide a round baler which would insure obtaining, after a stoppage of the baler, a bale diameter which is substantially the same as a bale diameter obtained during normal operation of the baler. 
     SUMMARY OF THE INVENTION 
     These and other objects of the present invention, which would become apparent hereinafter, are achieved by providing a round baler the locking means of which includes means for latchingly connecting the front and rear housings in a partially open position of the rear housing. Research and practice have shown that a small, limited opening of the housing by about from 20 to about 100 mm is sufficient to provide for resumption of rotation of a bale and maintaining the rotation during tying-up of the bale because the reduction of the load of the compression elements, the reduction of the rolling resistance of the bale, and multiple overrunning of the bale by the compression elements at insufficient delivery of the crop provide for reduction of the bale diameter. A further advantage of the present invention consists in that the rear housing can again be pulled to its initial closing position during the tying-up process. This is possible because the bale expands by a relatively small amount as a result of the small, limited opening of the rear housing. 
     A constructionally simple locking device, which permits both a limited opening of the rear housing and its closing, includes, in accordance with the present invention, a locking pawl and a latching member cooperating with the locking pawl and formed as a rotatable eccentric or a rotatable cam rotatable between a first position, in which the rear housing is connected with the front housing in the closed position of the rear housing, and a second position in which the rear housing is connected with the front housing in the partially open position of the rear housing. Alternatively, the locking pawl-supporting axle can be formed as a rotable eccentric or a rotable cam. The latching member can be rotate manually, electrically, or hydraulically and be so dimensioned that it would provide for an opening distance from about 20 mm to about 40 mm. 
     In accordance with another embodiment of a locking device of the present invention, the locking device includes two pairs of locking pawls provided on opposite sides of the compression chamber. A locking nose of one of the locking pawls of each pair of locking pawls is offset, in the opening direction of the rear housing, with respect to a locking nose of another of the locking pawls of the pair by a distance corresponding to a desired distance the rear housing is to be moved by into its partially open position. During the normal operation of the baler, the locking pawl with the offset locking nose is located outside of the operational region of the latching member. The locking pawl with the offset locking nose is brought into a position, in which it cooperates with the latching member, only during a defective operation. It engages the latching member after the first locking pawl has been released and the rear housing has been pivoted to its partially open position. The locking pawl with the offset locking nose is released after the formation of a bale, including tying-up, has been finished, thus providing for complete openings of the rear housing and ejection of the finished bale. 
     In a particular advantageous embodiment of locking device according to the present invention, there is provided means which displaces the rear housing after its partial opening into the original closed position. This permits to resume rotation of the bale after its stoppage and insures obtaining of a bale diameter corresponding to a predetermined bale diameter. 
     The novel features of the present invention, which are considered as characteristic for invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 shows a schematic side view of a round baler with a conventional locking device; 
     FIG. 2 shows a schematic side view of a major portion of a locking device according to the present invention in a closed operational position of the rear housing; 
     FIG. 3 shows a view similar to that of FIG. 2 in a partially open locking position of the rear housing; 
     FIG. 4 shows a schematic side view of a major portion of another embodiment of a locking device according to the present invention in a closed operational position of the rear housing; 
     FIG. 5 shows a view similar to that of FIG. 4 in a partially open locking position of the rear housing; 
     FIG. 6 shows a schematic side view of a major portion of yet another embodiment of a locking device according to the present invention in a closed operational position of the rear housing; 
     FIG. 7 shows a view similar to that of FIG. 6 in a partially open locking position of the rear housing; 
     FIG. 8 shows a view similar to that of FIG. 6 of a modified embodiment of a locking device according to the present invention; 
     FIG. 9 shows a schematic side view of a major portion of a further embodiment of a locking device according to the present invention in a closed operational position of the rear housing; 
     FIG. 10 shows a view similar to that of FIG. 9 in a partially open locking position of the rear housing; 
     FIG. 11 shows a schematic side view of a major portion of a still further embodiment of a locking device according to the present invention in a closed operational position of the rear housing; 
     FIG. 12 shows a view similar to that of FIG. 11 in a partially open locking position of the rear housing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A round baler, which is shown in FIG. 1, includes a chassis I that carries or supports a cylindrical compression chamber housing. The compression chamber housing is formed of a front housing  2 , which is fixedly secured to the chassis  1 , and a rear housing  4 . The rear housing  4  is pivotally connected with the front housing  2  by an upper axle  3  supported in the front housing  2 . Radially, the compression chamber housing is formed by compression elements such as, e.g., belts or conveyor chains (not shown) or rolls  5  which are rotatably secured partially in the front housing  2  and partially in the rear housing  4 . The rolls  5  limit a constant volume, compression chamber  6 . Axially, the compression chamber housing is limited by front side walls  7  of the front housing  2 , which are spaced from each other by a distance corresponding to the width of to-be-formed bales, and by rear side walls of the rear housing  4 , which are likewise spaced from each other by a distance corresponding to the width of the to-be-formed bales. In a closed position of the rear housing  4  which is designated with a reference numeral  9 , the front edges  10  of the rear side walls lie on the rear edges  11  of the front side walls  7 . In the lower region, each side wall  7  is supported outside of a locking pawl  12 , which is connected to the front side wall  7 , on a bolt  13 . Each locking pawl  12  engages a latching peg  14  secured to the rear housing  4 . The locking pawls  12 , thus, connect the front housing  2  with the rear housing  4 . The release of the locking pawl  12  is effected with a connection rod  15 , which is actuated by a hydraulic cylinder  16 , to make pivoting of the rear housing  4  possible, in per se known manner. 
     For delivery of the to-be-released harvest product into the compression chamber the compression chamber housing has, in its front portion, a delivery slot  17 . The harvest product is fed to the delivery slot  17  and subsequently into the compression chamber  6  by a pick-up drum  18 . The harvest product is formed into a bale by the driven rolls  5 . 
     As shown in FIG. 2, the locking pawl  19  of the locking device according to the present invention has, in addition to a first locking nose  20 , which connects the front and rear housings  2  and  4  in the locking operational position of the rear housing designated with a reference numeral  21 , a second locking nose  22  spaced from the first locking nose  21  in a rightward direction by from about 20 mm to about 100 mm, i.e., in an opening direction of the rear housing  4 . The second locking nose  22  is offset downwardly with respect to the first locking nose  21 . After the locking pawl  19  has been lifted off the latching peg  14 , the rear housing  4  pivots automatically under pressure which is applied by a bale, which still remains in the compression chamber, into an opening direction  23  and is locked in a partially open position  24  by the second locking nose  22 , as shown in FIG.  3 . The partially open position of the rear housing  4  provides for rotation of the bale and its tying. After the second locking nose  22  is released, and the rear housing  4  is pivoted by about 90°, the bale is ejected. After the bale has been ejected, the rear housing  4  is pivoted in the opposite, closing direction and is locked in its locking operational position  21  by the first locking nose  20 . 
     In the embodiment shown in FIG. 4, there is provided, in addition to a first locking pawl  25 , a second locking pawl  26 . The second locking pawl  26  is supported on a stationary peg  27  coaxially to the first locking pawl  25 . The second locking pawl  26  project beyond the first locking pawl  25  by from about 20 mm to about 100 mm, i.e., it is longer than the first locking pawl  25  by that amount, as can be seen in FIG.  4 . In the locking mechanism shown in FIG. 4, the first locking pawl has a first locking nose  28 , and the second locking pawl  26  has a second locking nose  29 , which is displaced, in the opening direction  30  of the rear housing  4 , by from about 20 mm to about 100 mm, i.e., by an amount by which the length of the second locking pawl  26  exceeds the length of the first locking pawl  25 . In the embodiment of FIG. 4, in its closed position  31 , the rear housing  4  is connected with the front housing  2  by the first locking pawl  25 . Actuation and holding means (not shown) holds the second locking pawl  26 , during the normal operation of the baler, outside of the engagement region of the second locking pawl  26  with a latching peg  32  secured to the rear housing  4 . The bale ejection takes place upon disengagement of the first locking pawl  25  from the latching peg  32  and upon pivoting of the rear housing by 90°. 
     If a bale remains in the compression chamber  6  during the operation of the baler, which is sensed by a suitable sensor or, in case a cam decoupling clutch is used, is signalized by an acoustic signal (rattle), or by non-feed in the pick-up region, the delivery of the crop is stopped, the second locking pawl is brought in the same position as the first locking pawl  25  and the first locking pawl  25  is disengaged from the latching peg  32 , see FIG.  5 . Upon the disengagement of the first locking pawl  25  from the latching peg  32 , the rear housing  4  pivots in the opening direction  30  by a distance  33  and is held in the partially open position  34  by the second locking pawl  26  the locking nose  29  of which engages the latching peg  32 . Upon actuation of the baler drive, the rotation of the bale resumes, it is tied up, and upon disengagement of the second locking pawl  26  from the latching peg  32  and opening of the rear housing  4 , the tied bale is ejected from the compression chamber  6 . 
     In the embodiment shown in FIGS. 6,  7 , a locking pawl  35  cooperates with a latching member formed as a rotatable eccentric disc  36 . As shown in FIG. 6, in the closed position of the rear housing  4 , the eccentric portion  37  of the disc  36  is engaged by a locking nose  39  of the locking pawl  35 . To provide for a partially open position  40  shown in FIG. 7, the eccentric disc  36  is rotated by 180°, whereby the rear housing  4  pivots in the opening direction  42  by an amount of the eccentricity  41 . The actuation of the eccentric disc  36  can be effected manually, electrically, or hydraulically, e.g., when a baler includes a hydraulic cylinder (not shown). 
     In the embodiment shown in FIG. 8, instead of the eccentric disc  36 , a rotatable cam  43  is provided. The cam  43  functions in the same way as the eccentric disc  36 . Alternatively, a locking pawl-supporting axle  44  can be formed as a rotatable eccentric disc or as a rotatable cam. 
     In the embodiment shown in FIGS. 9-10, a first locking pawl  45  is, e.g., mechanically connected with a second locking pawl  46  having a locking nose  48  offset, in the opening direction of the rear housing  4 , with respect to a locking nose  47  of the locking pawl  45 . 
     During normal operation of the baler, both locking pawls  45 ,  46  pivot simultaneously, and only the first locking pawl  45  engages the latching peg  32  in the closed position of the rear housing  4 . In case of a defective operation, the second locking pawl  46  is decoupled from the first locking pawl  45  and, after the disengagement of the first locking pawl  45  from the latching peg  32 , engages the latching peg  32 , as shown in FIG. 10, providing for retaining of the rear housing  4  in a partially open position  49 . 
     In the embodiment shown in FIGS. 11-12, the support axle  50  of the locking pawl  41  is not stationary, but is pivoted or displaced by appropriate auxiliary means, e.g. by a hydraulic cylinder  54 . Alternatively, the latching peg  52  can be made displaceable or pivotable. As shown in FIGS. 10-11, the locking pawl  51  is hingedly connected with the front housing  2  by a fishplate pair  53  and is connected with the double-action hydraulic cylinder  54 . During the normal operation, a predetermined pressure, which is maintained in the hydraulic cylinder  54 , provides for holding the front and rear housings  2  and  4  in their closed, operational position  55 . The piston stroke of the hydraulic cylinder  54  is so selected that it can be changed within a range of 20-100 mm. In case of a defective operation, the pressure in the cylinder  54  is reduced, and the piston moves to its end position  56 , a shown in FIG. 12, providing for pivoting of the rear housing  4  to its partially open position  57 . 
     After the necessary pivotal movement of the bale, the rear housing  4  can be, in advantageous manner, pivoted back to its closed position by applying pressure to the rod side of the piston. Thereafter, tying of the bale takes place. 
     It is particularly advantageous to be able to sense the rotation of a bale or the actuation of an overload coupling, and effect automatically a partial opening and locking of the rear housing in response to a sensing signal, and, simultaneously, to output to a tractor driver an alarm signal indicating a defective operation. 
     Accordingly, though the present invention was shown and described with references to the preferred embodiments, such are merely illustrative of the present invention and are not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.