Abstract:
A baler having a reciprocating plunger within a main bale chamber for compressing crop material into bales. The plunger has a first guide mechanism for permitting linear movement within the main bale chamber that allows a pivoting of an end face. A second guide mechanism includes a slot allowing the plunger to be oriented so that the second edge of the end face compresses crop material first and then subsequently pivots to compress equally and finally to have the second edge leading the first edge of the end face away from the bale to provide greater bale compression without additional force.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This application claims foreign priority under 35 U.S.C. §119 to Belgian Application BE2014/0509 filed Jul. 3, 2014 titled “PLUNGER FOR SQUARE BALER” and having Yannic Vande Ryse and Johan A. E. Vande Ryse as the inventors. The full disclosure of BE2014/0509 is hereby incorporated herein by reference. 
         [0002]    1. Field of the Invention 
         [0003]    The present invention relates to agricultural balers and more specifically for plungers used in 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 first slot  82  formed in the side walls of the bale chamber, with the plunger first slot  82  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]    One of the desirable outcomes in forming a bale is to have a bale with greater density of crop material. This is achieved by increasing the resistive force as the plunger compresses crop material within the main bale chamber. However, in so doing, the forces reacting on the plunger and the mechanism for reciprocating the plunger begin to increase which is not desirable for long-term operation. 
         [0012]    US20110/0107588 describes a baler having a plunger with a pivoting point, where the pivoting point travels in the guiding channel. A linkage is provided between the plunger and a rotating drive element such that the plunger is moved forward and backwards in the guiding channel. The plunger has a face configured to have a line of loading. This line of loading shifts across the face as the linkage drives the plunger forwards and backwards in the guiding channel. The linkage directly drives the plunger without an intervening pivoting linking member, as is the case in most prior art balers. However, the line of loading from this plunger is such that first, the lower part of the newly fed crop material is compressed, and in a second phase the upper part since the rocking of the plunger starts below and moves in an upward rotation. 
         [0013]    While others have proposed complex balers and mechanisms to reduce force applied to the plunger, they suffer from complicated mechanisms and the inevitable additional cost in an attempt to achieve such a goal. 
         [0014]    What is needed in the art therefore, is a simplified and effective way to minimize reaction forces on a plunger while increasing bale density. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention provides increasing bale density without significantly increasing the reactive forces on a plunger. 
         [0016]    The invention, in one form, is directed to a baler including a main bale chamber having upper, lower and side walls with the main bale chamber having an outlet for discharge of compressed crop material into bales. A plunger is reciprocated within the main bale chamber between a first position away from the outlet and a second position towards the outlet, the plunger having an end face with first and second edges for compressing crop material in the main bale chamber. A mechanism reciprocates the plunger within the main bale chamber between the first and second positions. An opening in one of the side walls has a front edge and is positioned to permit entry of crop material into the main bale chamber when the plunger is in the first position, the first edge of the plunger end face sweeping over the opening when the plunger is translated between the first and second positions. The invention is characterized by a first guide mechanism for translation of the plunger between the first and second positions, the first guide mechanism permitting pivoting of the plunger about an axis substantially parallel to the front edge of the opening. A second guide mechanism is connected between at least one of the main bale chamber walls and the plunger the first and second mechanisms cooperating to place the plunger in the first orientation so that the second edge of the plunger end face compresses crop material first when the plunger is in the first position and in between the second plunger position orients the plunger end face so that both edges compress the crop material equally, the second guide mechanism providing a predetermined translation from the first to the second orientation. 
         [0017]    An advantage of the present invention is that the bale density is increased while the reactive loads on the plunger are not increased which facilitates compression of bales and reciprocation of the plunger. 
     
    
     
       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 plunger of the present invention; 
           [0020]      FIG. 2  is a schematic side view of a plunger incorporating the present invention (shown in a first position) that may be used in the baler of  FIG. 1 . 
           [0021]      FIG. 3  is a schematic side view of the plunger of  FIG. 2 , shown in a second position. 
           [0022]      FIG. 4  is a schematic side view of the plunger of  FIG. 2 , shown in a third position. 
       
    
    
       [0023]    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 
       [0024]    Referring now 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 stuffer 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. 
         [0025]    Plunger  30  is connected via a crank arm  40  with a gear box  42 . Gear box  42  is driven by a flywheel  44 , which in turn is connected via a drive shaft  46  with the power take-off (PTO) coupler  48 . The PTO coupler  48  is detachably connected with the PTO spline at the rear of the traction unit, such as a tractor (not shown). PTO coupler  48 , drive shaft  46  and flywheel  44  together define a portion of a driveline  50  which provides rotative power to gearbox  42 . Flywheel  44  has a sufficient mass to carry plunger  30  through a compression stroke as power is applied to drive shaft  46  by the traction unit. 
         [0026]    Referring now to  FIG. 2 , there is shown, in schematic fashion, the baler  10  having the main bale chamber  26  in which the plunger  30  reciprocates to form crop material  52  into a completed bale  52 . The crank arm  40  causes the plunger  30  to reciprocate and move along upper and lower walls  56 ,  58  respectively and sidewalls  60  towards the outlet  32  through which the bales  54  are ejected. The plunger  30  is reciprocated between a first position  62  shown in dashed lines in  FIG. 2  and a second position  64  shown in a dashed vertical line. Plunger  30  has an end face  66  with a first edge  68  and a second edge  70 . The first edge  68  sweeps over a crop opening  72  as the plunger  30  is reciprocated within main bale chamber  26 . Crop opening  72  has a front edge  74  which is generally at a right angle with respect to the longitudinal axis of main bale chamber  26 . 
         [0027]    As plunger  30  is reciprocated within main bale chamber  26 , it is acted on by a first guide mechanism  76  and a second guide mechanism  78 . The crank arm  40  reciprocating the plunger  30  is pivotally connected to plunger  30  at a pivotal connection  80 . The first guide mechanism  76  includes a first slot  82  in side wall  60 . First slot  82  is straight and is generally parallel to the longitudinal axis of main bale chamber  26 . A roller  84  is received in the slots  82  on both side walls  60  so as to maintain the plunger within the main bale chamber  26  but at the same time permit limited pivoting of the plunger  30 . Tapered upper and lower walls  86  on plunger  30  provide clearance for the limited pivoting of the plunger. 
         [0028]    The second guide mechanism  78  includes a second slot  88  in the sidewalls  60 . Second slot  88  has a first section  90  which is parallel to first slot  82  and spaced at a distance from first slot  82  so that a roller  92  on plunger  30  causes the orientation of end face  66  as shown in  FIG. 1 . Second slot  88  has a second section  94  in which a predetermined transition of roller relative to first slot  82  takes place. The second slot  88  has a third section  96  in which the section is substantially parallel to first slot  82  but brings the roller  92  closer to first slot  82 . 
         [0029]    The pre-compression chamber  22  sequentially introduces the crop material  52  through opening  72  into main bale chamber  26  by stuffer forks  28 . In operation, the reciprocating mechanism continuously reciprocates plunger  30  between first position  62  and the second position  64 . This movement of the plunger  30  is synchronized with the entry of crop material  52  to produce the flakes that ultimately make up the completed bale  54 . The plunger  30  is guided into one of three orientations relative to main bale chamber  26  as the plunger  30  is reciprocated. These orientations are set by the second guide mechanism  78 . As shown in  FIG. 2 , the roller is in the first section  90  where the plunger  30  is at or near its first position  62 . In this section, the end face  66  is oriented so that the first edge  68  of the end face  66  sweeps across the front edge  74  of crop opening  72  and the second edge  70  leads the first edge  68  and compresses crop material first. 
         [0030]    As the plunger  30  continues its movement, it passes into the orientation of  FIG. 2  set by section  94  of second slot  88 . In this position, the edges  68  and  70  of the end face  66  press equally on the crop material. As the plunger  30  continues its movement towards its second position  64 , it assumes the orientation shown in  FIG. 4  where the first edge  68  of end face  66  is closer to the second plunger position  64  than the second edge  70 . This facilitates movement of the plunger  30  and completed bale  52  as the plunger  30  returns to its first position  62 . 
         [0031]    The mechanism described above enables a significantly increased bale density without significant additional reactive forces on the plunger  30 . This is done with a mechanism that is greatly simplified and economical. The provision of the slot for the second guide mechanism  78  enables the orientation of end face  66  to be flexibly and in a predetermined manner moved from the first orientation of the first position  62  to the second orientation as the plunger  30  moves toward its second position  64 . This allows the plunger orientation to be controlled for particular desired applications. Although the first guide mechanism  76  is shown with a straight line movement and the second guide mechanism  78  is shown with straight and curved movement, the contours of both may be arranged to produce the desired orientation. 
         [0032]    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.