Patent Abstract:
A large square baler includes a crop compressing plunger constructed in a modular fashion comprising a main support frame to which right and left plunger end sections and a plurality of identical individual cast plunger middle sections are bolted in side-by-side, spaced relationship to each other, with the space between adjacent sections defining a pathway through which a twine-delivery needle may pass to deliver twine to a knotter assembly when it is desired to secure a formed bale by tying lengths of twine about the bale.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates to balers for making large parallelepiped bales, and more particularly, relates to plungers for such balers. 
     BACKGROUND OF THE INVENTION 
     Modern plunger designs require complex sheet metal weldments. The weldments are made up of stiffeners, cross-members, needle guides, shim rollers or plates, plunger guide skis and knives. This type of construction results in high production costs. Additionally, when plunger damage occurs, serviceability to repair damaged sections is very difficult as it may require the entire plunger to be removed even though the damage may be localized. 
     SUMMARY OF THE INVENTION 
     According to the proposed invention, there is provided an improved baler plunger construction, and more specifically, there is provided a construction which overcomes the aforementioned drawbacks of the prior art plungers. 
     An object of the invention is to provide a simple baler plunger construction which may be easily repaired. 
     The foregoing object is accomplished by making the baler plunger of a modular design so as to include a main carrier frame to which a plurality of cast plunger sections are bolted in side-to-side relationship to each other. 
     This and other objects will become apparent with a reading of the ensuing description together with the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic left side view of a large square baler having left side structure removed to reveal the inside of the baling chamber. 
         FIG. 2  is a left front perspective view of a baler plunger constructed in accordance with the principles of the present invention, with parts being removed to show mounting structure. 
         FIG. 3  is a left front perspective view of the baler plunger shown in  FIG. 2 . 
         FIG. 4  is a right front perspective view of the support frame of the plunger. 
         FIG. 5  is a left front perspective view of the right-hand plunger end section. 
         FIG. 6  is a lower, left front perspective view of one of the plunger middle sections. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to  FIG. 1 , there is shown a baler  10  for forming large parallelepiped bales and including a main frame  12  supported on a tandem set of ground wheels  14 . A draft tongue  16  projects forwardly from the front of the frame  12  and is adapted for attachment to a towing vehicle such as an agricultural tractor, not shown. A baling chamber  18  includes parallel top and bottom walls  20  and  22 , respectively, and opposite, parallel side walls  23 , which are all arranged so that the baling chamber  18  has a square or rectangular cross section. The bottom wall  22  is provided with a crop inlet  24  to which is coupled the upper end of a pre-compression chamber  26  in the form of a duct that curves upwardly and rearwardly from a crop pick-up  28 . Located in the region between the pick-up  28  and the pre-compression chamber  26  is a feeder fork arrangement  30  that operates to positively move crop into the forward end of the chamber  26 . Transversely spaced tines  32  of a pivotally mounted crop blocking fork  34  are selectively movable between forwardly pivoted, crop-retaining position, wherein they extend over an upper edge of a back wall of the pre-compression chamber  26  and into the chamber  26  at a location adjacent the baling chamber inlet  24 , and a rearwardly pivoted crop-release position, (as shown) wherein they are removed from the pre-compression chamber  26  for permitting an accumulated charge of crop to be moved into the baling chamber  18  through operation of a stuffing fork  36  having transversely spaced tines that move down through slots provided in a front wall of the pre-compression chamber, and then sweep upwardly through the chamber  26  to move the charge of crop into the baling chamber  18 . Appropriate actuators, not shown, are associated with the blocking fork  34  and stuffing fork  36 , and are associated with controls that are sequenced to effect retraction of the blocking fork  34  and then operation of the stuffing fork  36  once the charge of crop has reached a preselected density as determined by a spring loaded, density sensing door  38 . 
     Once the charge of crop has been moved into the baling chamber  18 , it is moved rearwardly by operation of a plunger drive  40  acting on a plunger  42  which compresses the charge of crop against a partially formed bale  44  and a completely formed bale  46  which has already been bound together by several transversely spaced loops of twine that have been placed there by operation of a twine tying arrangement comprising a needle yoke  48 , which is pivotally mounted and includes a plurality of laterally spaced needles  50  for delivering twine to a knotting arrangement  52  mounted across the top wall  20  of the baling chamber, by way of slots (not shown) provided in the bottom wall  22  of the baling chamber  18 . 
     The plunger drive  40  may be of any known construction, but here is disclosed as including an extensible and retractable hydraulic drive cylinder  54  having its cylinder end anchored to the frame  12  by a coupling pin  56 , and having its rod end pivotally coupled, as at a pin  58 , to a crank arm  60 . The crank arm  60  is mounted for oscillating about a horizontal transverse axis defined by a pin  62  coupling the forward end of the crank arm  60  to the frame  12 . The rear end of the crank arm  60  is pivotally coupled, as by a coupling pin  64 , to the forward ends of a parallel pair of transversely spaced connecting rods  66  having their rear ends pivotally coupled to the plunger  42  by respective coupling pins  68 . The hydraulic drive cylinder  54  is shown retracted in  FIG. 1 , this position corresponding to that where the plunger  42  is fully extended so that its rear face is located to the rear of the inlet  24  to the baling chamber  18 , with extension of the cylinder  54  causing the plunger  42  to move forwardly to a position wherein the rear face of the plunger  42  is located forwardly of the chamber inlet  24 . 
     Referring now also to  FIGS. 2 ,  3  and  4 , it can be seen that the plunger  42  is of a modular construction and includes a carrier frame  70  including vertically spaced, parallel, top and bottom cross members  72  and  74 , respectively, which for the main part are T-shaped in cross section. The stem of the T of the top cross member  72  is defined by a horizontal plate  76  having a top surface machined at its opposite ends to define mounting surfaces, with a rear edge of the plate  76  being joined along its length to a vertical rear rectangular plate  78 , which defines the top of the T and includes a machined upper mounting surface. Lower corner regions at the opposite ends of the vertical plate  78  are removed to define notches  80  having a purpose explained below. The stem of the T of the bottom cross member  74  is defined by a horizontal plate  82  having a rear edge joined along its length to a vertical rear rectangular plate  84  disposed in co-planar relationship to the vertical plate  78  of the top cross member  72  and defining the top of the T. Fore-and-aft extending, vertical mounting flanges  86  are joined to opposite ends of each of the horizontal plate  82  and a lower part of the vertical plate  84 . Extending between, and having opposite ends welded to, right and left end regions of the top and bottom cross members  72  and  74  are right and left pairs of fore-and-aft extending, parallel, vertical connecting rod mounting plates  88  and  90 , respectively. The pairs of mounting plates  88  and  90  are generally configured as equilateral triangles with front sides of the plates being disposed vertically and with front sides of the plates including rounded forward corners disposed forwardly of first and second sets of axially aligned, horizontal cylindrical bushings  92  and  94 , respectively, that are provided in middle regions of the right and left pairs of upright members  88  and  90  and serve to receive the mounting pins  68  for connecting the right and left connecting rods  66  to the plunger  42 . 
     Referring now also to  FIGS. 5 and 6 , it can be seen that the plunger  42  includes right and left plunger end sections  96  and  98 , respectively, and five identical middle plunger sections  100 . The right and left plunger end sections  96  and  98  are mirror images of each other, with only the left plunger end section  98  being shown in detail (see  FIG. 5 ) and with it to be understood that any feature described as pertaining to the left plunger end section  98  also pertains to the right plunger end-section  96 . The plunger end sections  96  and  98  are each in the form of a casting and respectively include fore-and-aft extending, main body portions in the form of vertical flat plates  102 R and  102 L having rear regions including top and bottom edges which converge forwardly to respective corner regions provided with horizontal, outwardly projecting, cylindrical, front roller axle mounts  104 R and  104 L that are in axial alignment with each other. Identical rear roller axle mounts  106 R (not visible) and  106 L are respectively provided at rear regions of the plates  102 R and  102 L in horizontal alignment with the front axle mounts. Rollers (not shown) carried on axles received in the mounts are received within horizontal roller guide tracks  108  (see  FIG. 1 ) provided in the side walls  23  of the baling chamber  18  so as to prevent the plunger  42  from cocking up or down within the baling chamber  18  during operation. Formed integrally with the upper edges of the plates  102 R and  102 L are L-shaped mounting pads  109 R and  109 L, with opposite ends of the horizontal and vertical plates  76  and  78 , respectively, of to top cross member  72  of the frame  70  engaging the pads, with it being noted that the notches  80  permit the vertical plate  78  be located on top of the mounting pads. The opposite ends of the horizontal plate  76  are each provided with a pair of mounting holes  110  that are disposed in axial alignment with holes  112  provided in a horizontal leg of each of the pads  109 R and  109 L, while horizontal holes  113  provided in opposite ends of the vertical plate  78  are disposed in alignment with threaded bores  114  provided in the vertical leg of each of the pads  109 R and  109 L. For securing the cross member  72  of the frame  70  to the plunger end sections  96  and  98 , first mounting bolts  115  are inserted through the aligned holes  110  and  112  and have threaded ends receiving nuts (not visible), while second mounting bolts  116  are inserted into the holes  113  and threaded into the bores  114 . Provided on each of the plates  102 R and  102 L so as to be in horizontal alignment with the mounting flanges  86  is a mounting pad  118  that contains a pair of horizontally disposed holes  120  that are aligned with a pair of holes  122  provided in each of the flanges  86 , with bolts  124  being received in the aligned holes and having nuts  126  tightened onto inner threaded ends so as to secure central lower regions of the module end sections  96  and  98  to lower cross member  74  the frame  70 . 
     The plates  102 R and  102 L, respectively of the plunger end sections  96  and  98 , include profiles located forwardly of the connection frame  70  that are each defined by top and bottom horizontal edges joined to a vertical edge. Respectively joined to this profile of the plates  102 R and  102 L are outwardly projecting flanges  130 R and  130 L. The flanges  130 R and  130 L define vertical, rearwardly facing, crop-engaging surfaces  132 R and  132 L, with stiffness being afforded to the plates  102 R and  102 L by forming the flanges so that they define upper, rearwardly opening U-shaped pockets  134 R,  134 L and lower, rearwardly opening, U-shaped pockets  136 R and  136 L in the crop-engaging surfaces. The vertical crop engaging surfaces  132 R and  132 L respectively include upper sections located above the upper pockets  134 R and  134 L that are provided with three carriage bolt mounting holes  136  located in a triangular pattern, and art outer pair of outer bale corner-forming plunger teeth  138  are each provided with three mounting holes which are aligned with the holes  136  and respectively receive a set of three carriage bolts  140  having threaded ends on which nuts  142  are provided for holding the plunger teeth  138  in place so that they project upwardly and rearwardly from an upper rear corner of the flanges  130 R and  130 L. For the sake of clarity, only the tooth  138  of the plunger end section  98  is shown. The flanges  130 R and  130 L also include respective horizontal bottom sections having rear end regions provided with a pair of mounting holes  144 , with outer horizontal plunger knife segments  146  being respectively bolted to the bottom flange sections by bolts (not shown) projecting upwardly through holes provided in the knife segments  146  in alignment with the holes  144 , with nuts being received on threaded upper ends of the bolts to hold the knife segments  146  in place. For the sake of simplicity, the knife segments  146  appear only in  FIG. 3 . 
     The plunger middle sections  100  are spaced transversely from each other and from the plunger end sections  96  and  98  by equal amounts so as to define six vertical, needle clearance slots  148  for permitting passage of the twine-delivery needles  50  for delivering twine to the twine knotting assembly  52  during tying of twine about a finished bale  46 . Each plunger middle section  100  is fabricated as a casting defining transversely spaced right- and left-hand, vertical sides  150 R and  150 L (see  FIG. 6 ) joined by a vertical rear side  152  that defines a crop-engaging surface. The tops of each of the sides  150 R and  150 L are horizontal and include respective upper, thickened front regions  154 R and  154 L having vertical front surfaces provided with horizontal, threaded bores  156 . The sides  150 R and  150 L respectively include bottom rear inwardly offset regions  158 R and  158 L having bottom regions joined by a horizontal mounting pad  160  containing vertical threaded bores  162 , with a horizontal plunger knife section  164  being secured to each pad  160  by a pair of bolts (not shown). The sides  150 R and  150 L have bottom edges which extend first horizontally from the rear end and then are inclined upwardly and forwardly to front ends of thickened lower front regions  166 R and  166 L that extend horizontally toward the rear and have vertical forward surfaces that are co-planar with the vertical front surfaces of the thickened front regions  154 R and  154 L. A further set of horizontal threaded bores  156  are provided in the front surfaces of the thickened lower front regions  166 R and  166 L. The rear surface of the upper thickened regions  154 R and  154 L of each plunger section  100  is disposed in engagement with the rear surface of the vertical plate  78  of the upper cross member  72  of the frame  70 , while the rear surface of the lower thickened regions  166 R and  166 L of each plunger section  100  are disposed in engagement with the rear surface of the vertical plate  84  of the lower cross member  74 . The vertical plate  78  of the upper cross member  72  is provided with a plurality of horizontal holes  168  that are respectively axially aligned with the upper set of threaded bores  156  of each of the middle plunger sections  100 , while the vertical plate  84  of the lower cross member  74  is provided with a plurality of horizontal holes  170  that are respectively axially aligned with the lower set of threaded bores  156  of each of the plunger sections  100 . A plurality of bolts  172  project rearwardly through the horizontal holes  168  and  170  and are threaded into the holes  156  (the bolts  172  that extend through the vertical plate  84  are not visible) thereby securing the middle plunger sections  100  to the frame  70 . 
     As can be seen in  FIGS. 2 and 3 , the upper rear region of the middle plunger sections  100  are each provided with a triangular arrangement of carriage bolt holes  174 , and a plurality of middle plunger teeth  176  are respectively provided with matching sets of holes and receive mounting bolts  178  that project rearwardly through the holes  174  in the plunger sections  100  and in the matching holes provided in the plunger teeth  176 , with nuts  180  being received on rear threaded ends of the bolts so as to secure the teeth  176  in place where they project upwardly and rearwardly from the middle plunger sections  100 . 
     Thus, it will be appreciated that because the plunger  42  uses cast sections in place of complex weldments, as used in the prior art, part count and complexity is reduced. Fewer and simpler plunger components reduce manufacturing costs by decreasing assembly time, reducing floor space requirements, and eliminating fabrication operations. Increased stiffness results in smaller plunger knife deflection and increased cutting efficiency during flake cutoff. Furthermore, if the plunger  42  is damaged, service to individual plunger sections  96 R,  96 L or  100  can be performed often without removing the plunger  42  from the baling chamber  18 . 
     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.

Technology Classification (CPC): 0