Abstract:
A roll baler including circumferentially rotatable conveyor elements limiting a compression space therebetween, and a device for wrapping up a roll bale, which is formed in the compression space, with a section of a sheath web, the wrapping-up device including a pivotable start-up element for pressing the sheath web, against a surface of one of the rotatable conveyor elements, a separation element for cutting the sheath web off after the wrapping-up process ends and pivotable between cutting and non-cutting positions, and a common pivot axle for supporting the start-up element and separation element for pivotal movement.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a roll baler including circumferentially rotatable conveyor elements limiting a compression space therebetween, and a device for wrapping up a roll bale, which is formed in the compression space, with a section of a sheath web, the wrapping-up device including pivotable start-up means for pressing the sheath web, at least in an initial phase of a wrapping-up process, against a surface of one of the rotatable conveyor elements and separation means for cutting the sheath web off after the wrapping-up process ends and pivotable between cutting and non-cutting positions. 
     2. Description of the Prior Art 
     A roll baler of the type described above is disclosed in German Utility Model DE 296 12 863 UI. In the roll baler of this utility model, a sheath web is pressed by a pressure element against a side of a conveyor band remote from the compression space. The sheath web is delivered into the pressure space through an admission gap by a 180° deflection element. The drawback of such deflection of the sheath web, in particular with a conveyor bank having a specific texture, consists in that the sheath web is not always entrained by the belt. The separation device is supported on a second axle offset with respect to the pivot axle of the pressure element, and is connected mechanically with the pressure element. For cutting off the sheath web, the separation device should be pivoted over a relatively large arc over the pressure element and into a V-shaped guide of the pressure element. With such an arrangement many parts become necessary, on the one hand, and, on the other hand, the separation device requires a relatively large space for its installation and operation. However, the main drawback of the known device consists in an unreliable cut-off of the sheath web due to the fact that the sheath web and the separation device move both in the same direction. As a result, no definite edge of a cut can be produced. This results in that a poorly cut sheath web is partially taken up the separation device and/or is only partially removed from the conveyor band. In addition, a poor cut makes the introduction of the sheath web into the compression space more difficult. 
     Accordingly, an object of the present invention is to eliminate the above-discussed drawbacks of the wrapping-up means of the prior art roll baler. 
     SUMMARY OF THE INVENTION 
     This and other objects of the present invention, which will become apparent hereinafter, are achieved by mounting both the pressure element and the separation device on the same axle. In this way, the functions of starting the delivery of the sheath web and separation of the sheath web by pivoting the start-up device in one direction and the separation device in another, opposite direction are realized unexpectedly easily. This, in case an automatic control is used, permits to effect both functions with a single drive. In addition, the cutting direction of the separation device can be so selected that it would insure a good cut. Both the start-up device and the separation device have a simple construction, small dimensions, are reliable, substantially wear-free, require little maintenance, and are economical in manufacturing. 
     A common adjustment of both the start-up device and the separation device permits to provide a particularly simply, reliable and economical construction. 
     According to a preferred embodiment of the present invention, both the start-up device and the separation device are arranged in a common, pivotally supported frame. This permits to obtain a compact, rigid unit. 
     A particular reliable arrangement is obtained when the distance between the separation device and the pivot axle is smaller than a distance between the pivot axle and the start-up device, and the pivoting or drive means is connected with at least one of the pivot arms in which the pivot axle is supported. This arrangement, on one hand, provides for a sufficiently large distance between the band and the start-up device which permits the sheath web to be freely suspended in the intermediate space, preventing inadvertent entraining of the sheath web. On the other hand, the pivotal movement of the separation device is relatively small, with the prestressed sheath web having already passed past the separation device relatively far into the compression space. Furthermore, a direct drive is insured by connecting the drive means with one of the pivot axle-supporting arms. 
     In a further preferred embodiment of the present invention, the start-up device has a freely rotatable pressure roll. The pressure roll presses the sheath web against the conveyor band at least at the start of wrapping-up process and is rotated by the web. Then, the pressure roll pivots into the intermediate neutral position, and the formed roll bale pulls the sheath band directly from the supply roll. 
     The novel features of the present invention, which are considered as characteristic for the 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 
     The drawings show: 
     FIG. 1 a side view of a roll baler with start-up and separation devices according to the present invention; 
     FIG. 2 a front view of the roll baler shown in FIG. 1; and 
     FIG. 3 a side view of an alternative embodiment of a pressure element in form of a conveyor band. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The roll baler, which is shown in the drawings, essentially includes a housing  1  having a compression space  2  which is defined by two conveyor band segments  3  and  4 . Between the conveyor band sections  3 ,  4 , there is provided an admission gap  5  through which a to-be-compressed material is admitted from a feed chamber  6  above the feed table  7 . One of the conveyor band segments  3 ,  4 , namely, the segment  3  is located in a stationary housing port  8  and is supported by deflection and/or drive rollers  9 . The conveyor band segment  3  has a band section  10  which extends so far above the admission gap  5  that it forms a wall of the feed chamber  6 . The second conveyor band segment  4  is located in a housing part  13  foldable about an upper pivot axle  11  into a bale discharge position. 
     The housing  1  is limited, in the axial direction of the compression space  2 , by two side walls  14  which are spaced from each other by a distance corresponding to the width of the compression space  2 . The housing  1  is further limited by a rear wall  15  and by an upper cover  16 . 
     The housing  1  is further provided with a front wall  17 . Above the admission gap  5 , there is provided a wrapping-up device  18 . The wrapping-up device essentially includes a supply roller  20 , which is supported by support rollers  19 , a start-up device  22 , and a separation device  23 . The supply roller  20  carries a sheath web  21 , e.g., a net or foil. The start-up device  22  provides for take-off of the sheath web  21 , and the separation device  23  cuts the sheath web  21  after a predetermined amount has been wound down. 
     The support rollers  19  and the supply roller  20  are supported for rotation in the side walls  14  but remain stationary during operation of the baler. A sheath web section  24 , after being pulled from the supply roller  20 , runs substantially horizontally toward a deflection roller  25  and hangs therefrom after being deflected by 90°, substantially vertically downward at a distance from the conveyor band section  10 . The start-up device  22  and the separation device  23  are arranged on the opposite, with respect to the band section  10 , sides of the suspended section of the pulled-out sheath web  21  at a distance therefrom. 
     The start-up device  22  includes a pressure roll  27  which is rotatably supported in a pivot arms  26  and which extends essentially over the entire width of the compression space  2 . A cutting blade  28 , which forms the separation device  23 , is secured in the pivot arms  26  opposite the pressure roll  27 . The pressure roll  27 , the pivot arms  26 , and the cutting blade  28  form a rigid, rectangular frame  29  that is pivotably supported in the side walls  14  by a stationary axle  30 . The lever arm between the cutting blade  28  and the axle  30  is smaller than a lever arm between the axle  30  and the pressure roll  27 . A servo drive  31  is provided between the axle  30  and the pressure roll  27 . The servo drive  31  is connected to the side wall  14  at one of its ends and is connected, at its opposite end, to a pivot arm  26 . The servo drive  31  can be formed as an electric linear motor or as a hydraulic cylinder. 
     The start-up and separation devices  22 ,  23  operate as follows. 
     After a bale reaches a predetermined diameter, the frame  29  is pivoted, manually or by the servo drive  31  in a direction indicated by the arrow  32  into a start position shown in dash lines in which the pressure roll  27  presses the sheath web  21  against the band section  10  with a predetermined pressure. The band section  10 , which runs in the direction indicated by arrow  34  and is frictionally engaged with the sheath web  21 , carries the sheath web  21  through the admission gap  5  into compression space  2 . The servo drive  31 , which is time and space controlled, displaces the frame  29 , together with the cutting blade  28  and the pressure roll  27 , into a neutral position  35  shown in full lines, in which both the pressure roll  27  and the cutting blade  28  are inactive. In this position of the frame  29 , the rotatable, in the compression space  2 , roll bale pulls the sheath web  21  from the supply roller  20 . After reaching the desired degree of wrap-up, e.g., after three revolutions, the servo drive  31  displaces the frame  29  into its cutting position  36  shown in dash lines. In this position of the frame  29 , the cutting blade  28  is brought into engagement with the still running, sheath web  21  and cuts it off. Then, the servo drive  31  again pivots the frame  29 , together with the pressure roll  27  and the cutting blade  28  into the middle or neutral position  35 . After folding of the housing part  13 , the wrapped-up roll bale is expelled out of the compression space  2 , and a new cycle can begin. 
     In the embodiment shown in FIG. 3, instead of a pressure roll  27 , a conveyor band  37  supported by two deflection rollers  38  is used. The deflection rollers  38  are supported by a support element  39  which is supported in pivot arms  41  for pivotal movement about an axle  40 . The start position  42  of this arrangement is shown in dash lines. The advantage of the arrangement shown in FIG. 3 consists in that it insures a reliable entraining of the sheath web  43  as it provides for a large-surface contact of the web  43  with the conveyor band section  44 . The arrangement shown in FIG. 3 operates in the same manner as that shown in FIGS. 1-2. 
     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 to 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 embodiment or details thereof, and the present invention includes all of variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.