Abstract:
An agricultural baler includes a main bale chamber having a pair of opposed side walls, with each said side wall including a plunger slot arrangement defining a plunger slot. A pair of plunger slot rails are positioned in each plunger slot, including a top rail positioned at a top of a respective plunger slot and a bottom rail positioned at a bottom of a respective plunger slot. A plunger is reciprocally disposed within the main bale chamber. The plunger includes a pair of opposed sides and at least one roller extending laterally outward from each side, with each roller being positioned within a respective plunger slot. The baler is characterized by a pair of plunger slot cover assemblies, with each cover assembly being associated with a respective plunger slot and having an upper cover and a lower cover.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This application claims foreign priority under 35 U.S.C. §119 to Belgian Application BE2014/0511 filed Jul. 3, 2014 titled “PLUNGER SLOT COVER ASSEMBLY FOR AN AGRICULTURAL BALER” and having Ronald Biebuyck, Frederik Demon and Karel Naeyaert as the inventors. The full disclosure of BE2014/0511 is hereby incorporated herein by reference. 
         [0002]    1. Field of the Invention 
         [0003]    The present invention relates to agricultural balers, and, more particularly, to bale chambers within such balers. 
         [0004]    2. Description of the Related Art 
         [0005]    Agricultural harvesting machines, such as balers, are used to consolidate and package crop material so as to facilitate the storage and handling of the crop material for later use. In the case of hay, a mower-conditioner is typically used to cut and condition the crop material for windrow drying in the sun. In the case of straw, an agricultural combine discharges non-grain crop material from the rear of the combine defining the straw (such as wheat or oat straw) which is to be picked up by the baler. The cut crop material is typically raked and dried, and a baler, such as a large square baler or round baler, straddles the windrows and travels along the windrows to pick up the crop material and form it into bales. 
         [0006]    On a large square baler, a pickup unit at the front of the baler gathers the cut and windrowed crop material from the ground. The pickup unit includes a pickup roll, and optionally may include other components such as side shields, stub augers, wind guard, etc. 
         [0007]    A packer unit is used to move the crop material from the pickup unit to a duct or pre-compression chamber. The packer unit forms a wad of crop within the pre-compression chamber which is then transferred to a main bale chamber. (For purposes of discussion, the charge of crop material within the pre-compression chamber will be termed a “wad”, and the charge of crop material after being compressed within the main bale chamber will be termed a “flake”). Typically such a packer unit includes packer tines or forks to move the crop material from the pickup unit into the pre-compression chamber. Instead of a packer unit it is also known to use a rotor cutter unit which chops the crop material into smaller pieces. 
         [0008]    A stuffer unit transfers the wad of crop material in charges from the pre-compression chamber to the main bale chamber. Typically such a stuffer unit includes sniffer forks which are used to move the wad of crop material from the pre-compression chamber to the main bale chamber, in sequence with the reciprocating action of a plunger within the main bale chamber. 
         [0009]    In the main bale chamber, the plunger compresses the wad of crop material into flakes to form a bale and, at the same time, gradually advances the bale toward the outlet of the bale chamber. The plunger reciprocates, back and forth, toward and away from the discharge end of the baler. The plunger may include a number of rollers which extend laterally outward from the sides of the plunger. The rollers on each side of the plunger are received within a respective plunger slot formed in the side walls of the bale chamber, with the plunger slots guiding the plunger during the reciprocating movements. 
         [0010]    When enough flakes have been added and the bale reaches a full (or other predetermined) size, a number of knotters are actuated which wrap and tie twine, cord or the like around the bale while it is still in the main bale chamber. The twine is cut and the formed baled is ejected out the back of the baler as a new bale is formed. 
         [0011]    During the bale formation within the bale chamber, as described above, crop material can be forced through the plunger slots on opposite sides of the bale chamber. The crop material can accumulate outside of the bale chamber, such as in an area around the axle, or in an area between the twine box and the frame. It is thus necessary for the operator to periodically dismount from the traction unit and clean the crop from the baler. This takes time and effort on the part of the operator, reducing the baling efficiency of the baler. 
         [0012]    German patent document DD 288 309 B5 discloses a baler with a plunger slot arrangement having a panel that carries an upper guide rail and lower guide rail. Plunger rollers run between the guide rails. The panel provides the structural framework for the plunger slot arrangement, and appears to be formed as an extrusion which is closed on the side opposite from the plunger. Since the panel provides the structural support for the plunger slot arrangement, and also appears to be formed as an extrusion, the outside closed wall apparently extends the full length of the plunger slot arrangement. Crop material would tend to accumulate within the plunger slot, which in turn could negatively affect the reciprocating movement of the plunger rollers within the plunger slot. 
         [0013]    What is needed in the art is an agricultural baler which avoids problems of crop accumulation in the plunger slot and areas outside of the bale chamber. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention provides an agricultural baler with a plunger slot cover assembly for each plunger slot having a pair of plates positioned at the laterally inward edge of the plunger slot rails, such that the plates are positioned between the plunger and plunger slot rollers. 
         [0015]    The invention in one form is directed to an agricultural baler including a main bale chamber having a pair of opposed side walls, with each said side wall including a plunger slot arrangement defining a plunger slot. A pair of plunger slot rails are positioned in each plunger slot, including a top rail positioned at a top of a respective plunger slot and a bottom rail positioned at a bottom of a respective plunger slot. A plunger is reciprocally disposed within the main bale chamber. The plunger includes a pair of opposed sides and at least one roller extending laterally outward from each side, with each roller being positioned within a respective plunger slot. The baler is characterized by a pair of plunger slot cover assemblies, with each cover assembly being associated with a respective plunger slot and having an upper cover and a lower cover. The upper cover extends downward from the top rail and has a lower edge positioned between at least one respective roller and the plunger when the plunger is at a forward position. The lower cover extends upward from the bottom rail and has an upper edge positioned between at least one respective roller and the plunger when the plunger is at the forward position. 
         [0016]    An advantage of the present invention is that crop material is inhibited from entering the plunger slot. 
         [0017]    Another advantages is that crop material is inhibited from passing through the plunger slot and accumulating on the baler in an area outside of the main bale chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0019]      FIG. 1  is a perspective cutaway view showing the internal workings of a large square baler, which may include a main bale chamber with a plunger slot arrangement of the present invention; 
           [0020]      FIG. 2  is a perspective view of a portion of the baler shown in  FIG. 1 , including the plunger, plunger slot arrangement and pre-compression chamber, with the plunger at a rearward position at the end of return stroke position; 
           [0021]      FIG. 3  is another perspective view of a portion of the baler shown in  FIG. 1 , including the plunger, plunger slot arrangement and pre-compression chamber, with the plunger at a forward position at the end of compression stroke position; 
           [0022]      FIG. 4  is a side view showing the plunger and plunger slot arrangement, with the plunger at the end of compression stroke position; 
           [0023]      FIG. 5  is an end view of the plunger slot arrangement and a portion of the plunger, as viewed from the right side of  FIG. 4 ; 
           [0024]      FIG. 6  is a side view of the plunger slot rails and associated covers; and 
           [0025]      FIG. 7  is an end view of the plunger slot rails and covers, as viewed from the right side of  FIG. 6 . 
       
    
    
       [0026]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a perspective cutaway view showing the internal workings of a large square baler  10 . Baler  10  operates on a two stage feeding system. Crop material is lifted from windrows into the baler  10  using a pickup unit  12 . The pickup unit  12  includes a rotating pickup roll  14  with tines  16  which move the crop rearward toward a packer unit  18 . An optional pair of stub augers (one of which is shown, but not numbered) are positioned above the pickup roll  14  to move the crop material laterally inward. The packer unit  18  includes packer tines  20  which push the crop into a pre-compression chamber  22  to form a wad of crop material. The packer tines  20  intertwine the crop together and pack the crop within the pre-compression chamber  22 . Pre-compression chamber  22  and packer tines  20  function as the first stage for crop compression. Once the pressure in the pre-compression chamber  22  reaches a predetermined sensed value, a stuffer unit  24  moves the wad of crop from the pre-compression chamber  22  to a main bale chamber  26 . The stuffer unit  24  includes sniffer forks  28  which thrust the wad of crop directly in front of a plunger  30 , which reciprocates within the main bale chamber  26  and compresses the wad of crop into a flake. Stuffer forks  28  return to their original stationary state after the wad of material has been moved into the main bale chamber  26 . Plunger  30  compresses the wads of crop into flakes to form a bale and, at the same time, gradually advances the bale toward outlet  32  of main bale chamber  26 . Main bale chamber  26  and plunger  30  function as the second stage for crop compression. When enough flakes have been added and the bale reaches a full (or other predetermined) size, knotters  34  are actuated which wrap and tie twine around the bale while it is still in the main bale chamber  26 . Needles  36  bring the lower twine up to the knotters  34  and the tying process then takes place. The twine is cut and the formed bale is ejected from a discharge chute  38  as a new bale is formed. 
         [0028]    Referring now to  FIGS. 1-4 , conjunctively, the main bale chamber  26  includes a pair of side walls  40 , with each side wall  40  having a plunger slot  42  therein. Each plunger slot  42  has a longitudinal extension in the directions of reciprocating movement of the plunger  30 , and supports the plunger  30  during the plunger strokes within the main bale chamber  26 . Each plunger slot  42  is sized and configured to receive one or more rollers  44  which extend laterally from each side  46  of the plunger  30 . In the embodiment shown, a pair of substantially parallel plunger slot rails  48  are attached to the side walls  40  and define the plunger slot  42 . Each pair of plunger slot rails  48  includes a top rail  48 A and a bottom rail  48 B. The plunger  30  is shown with a pair of forward rollers  44 A and a pair of rearward rollers  44 B, which travel within a corresponding plunger slot  42 ; however, the number of rollers  44  extending from each side  46  can vary. Further, the plunger  30  can have an additional roller  50  extending from each side  46  which rotates about a vertical axis and engages a bottom rail  48 B and/or top rail  48 A to limit side to side movement of the plunger  30  during compression strokes. 
         [0029]    According to an aspect of the present invention, and referring now to  FIGS. 2-5 , each plunger slot  42  is partially covered with a plunger slot cover assembly  52  in a manner which inhibits crop from accumulating within the plunger slot  42 , and also inhibits the crop material from passing through the plunger slot  42  and exiting to the outside of the main bale chamber  26 . 
         [0030]    Each plunger slot cover assembly  52  includes an upper cover  54  and a lower cover  56 . The upper cover  54  is connected to and extends downward from a laterally inside edge  58  of the top rail  48 A. The upper cover  54  has a lower edge  60  which is positioned between at least one roller  44  and the plunger  30  when the plunger  30  is at the forward position. Likewise, the lower cover  56  is connected to and extends upward from a laterally inside edge  62  of the bottom rail  48 B. The lower cover  56  has an upper edge  64  which is positioned between at least one roller  44  and the plunger  30  when the plunger  30  is at the forward position. 
         [0031]    More specifically, the plunger  30  travels between a rearward position when at the end of a return stroke (as shown in  FIG. 2 ) and a forward position when at the end of a compression stroke (as shown in  FIG. 3 ). When the plunger  30  is at the rearward position, the exit of the pre-compression chamber  22  is open as shown in  FIG. 2 , and the front face of the plunger  30  is positioned to the rearward side of the exit of the pre-compression chamber, so that the pre-compressed crop material can be transferred into the main bale chamber  26 . Since this is the rearward most position of the plunger  30 , then the upper cover  54  and lower cover  56  need only extend over the portion of the main bale chamber  26  that is exposed to the crop material (i.e., the portion that is forward of the front face of the plunger  30  in  FIG. 2 ). In the illustrated embodiment, the upper cover  54  and lower cover  56  extend over an approximate forward half of the plunger slot  42 . However, the exact length of the upper cover  54  and lower cover  56  can vary, depending on the specific configuration of the main bale chamber. 
         [0032]    Referring now to  FIGS. 4-7 , the upper cover  54  is connected to a bottom surface  66  at the laterally inside edge  58  of the top rail  48 A. The upper cover  54  is constructed as a metal plate in the illustrated embodiment and is welded to the top rail  48 A. However, the upper cover  54  can be attached by other suitable attachment techniques, such as by using fasteners (e.g., screws) or an adhesive. The upper cover  54  can also be formed from other suitable materials, such as plastic or fiberglass. Further, the upper cover  54  can be attached to the laterally inside vertical edge of the top rail  48 A, or even possibly attached to the side wall  46  within the main bale chamber  26 . 
         [0033]    The lower cover  56  is connected to a top surface  68  at the laterally inside edge  62  of the bottom rail  48 B. The lower cover  56  is constructed as a metal plate in the illustrated embodiment and is welded to the bottom rail  48 B. However, the lower cover  56  can be attached by other suitable attachment techniques, such as by using fasteners (e.g., screws) or an adhesive. The lower cover  56  can also be formed from other suitable materials, such as plastic, fiberglass or rubber. Further, the lower cover  56  can be attached to the laterally inside vertical edge of the bottom rail  48 B. 
         [0034]    As best seen in  FIGS. 4 and 5 , as the plunger  30  travels forward during a compression stroke, the forward roller  44 A is positioned between the top and bottom rails  48 A and  48 B. The upper cover  54  and lower cover  56  are each positioned between the forward roller  44 A and the plunger  30  (see  FIG. 5 ). The forward roller  44 A is rotatably mounted to a roller shaft  70 , which in turn is mounted to and extends from the side  46  of the plunger  30 . The lower edge  60  of the upper cover  54  and the upper edge  64  of the lower cover  56  lie closely adjacent to the roller shaft  70  when the forward roller  44   a  is between the top and bottom rails  48 A and  48 B. The clearance distance between the roller shaft  70  and the top and bottom rails  48 A and  48 B is sufficient to inhibit contact therebetween, while at the same time keeping the distance between the rails  48 A and  48 B to a minimum to inhibit crop from entering the plunger slot  42 . 
         [0035]    The plunger slot arrangement can be provided with two pairs of optional scrapers  72  which further assist with inhibiting a buildup of crop material within plunger slot  42 . In the illustrated embodiment, the scrapers  72  associated with each plunger slot  42  are in the form of flat plates, with one plate located to the front side of the forward roller  44 A and the other plate located to the rear of the rearward roller  44 B. A number of brackets  74  are attached to the side  46  of plunger  30 , and each scraper  72  is bolted to a respective bracket  74  in a vertically adjustable manner using bolts  76 . Each scraper  72  can be positioned such that the bottom edge of the scraper  72  lies against or closely adjacent to the bottom rail  48 B, and in this manner removes crop material from the bottom of plunger slot  42  as the plunger  30  reciprocates within the main bale chamber  26 . The scrapers  72  shown in  FIGS. 2-5  are just one example of a scraper which effectively removes crop material from plunger slot  42 , and it will be appreciated that other configurations for the scrapers are also possible. 
         [0036]    During operation of baler  10 , plunger  30  reciprocates back and forth during compression strokes within the main bale chamber  26 . As the plunger  30  reciprocates back and forth, the rollers  44 A and  44 B likewise reciprocate back and forth within a respective plunger slot  42 . The movement of the rollers  44  causes a movement of air within the plunger slot  42  which acts to blow out or remove the crop material from the plunger slot  42 . The upper cover  54  and lower cover  56  are positioned in the forward portion of the plunger slot  42 , and are exposed to crop material within the main bale chamber  26 . The spacing between the upper cover  54  and lower cover  56  is such that the roller shaft  70  can pass therebetween during movement of the plunger  30 , while retaining a minimum distance to inhibit crop from entering the plunger slot  42 . The optional scrapers  72  also mechanically remove crop from within plunger slot  42 , and further cause air movement within the plunger slot  42  for removal of the crop material. 
         [0037]    While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.