Abstract:
A bunching saw assembly for a timber harvesting machine includes a vertical spindle which drives a horizontally oriented, rotary saw disc. Upper and lower bearing sub-assemblies support the spindle in a saw assembly housing. The bearing sub-assemblies include roller bearings which operate in separate bearing cavities, supplied with lubricant through independent lubricant inlet passages, and vented through independent lubricant vent passages.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to timber harvesting and, more particularly, to the construction and operation of a rotary bunching saw in a feller buncher machine. It relates specifically to the bearing lubrication system for the vertical spindle which supports a horizontally rotating saw disc in a bunching saw. 
     BACKGROUND OF THE INVENTION 
     The feller buncher attachment for a timber harvesting tractor conventionally has a horizontally rotating circular saw, or a horizontally operating shear, mounted in the attachment frame. In the rotary saw embodiment, the saw disc is mounted on the lower end of a vertical spindle supported for rotation in a housing on the attachment frame. A hydraulic motor mounted on top of the housing rotates the spindle and, accordingly, the saw disc. 
     In such a conventional bunching saw assembly, the spindle is supported in upper and lower bearings seated within the saw assembly housing. A vertically elongated cavity within the housing surrounds the shaft and contains the upper and lower bearings. The base of a drive motor body covers the top of the cavity and a main housing seal forms the bottom of the cavity. To lubricate the bearings, a grease zerk fitting is conventionally provided in the housing above the upper bearing and another is provided between the upper and lower bearings. 
     The amount of grease injected into the various cavities within the vertically elongated cavity is prescribed by the manufacturer and is based on specified hourly or daily consumption rates. Because the amount of grease consumed varies with operating conditions, more or less grease than that prescribed by the manufacturer may be consumed, however. If consumption is greater than anticipated, inadequate lubrication eventually results and bearing failure is possible. 
     Problems also result if grease consumption is less than anticipated. The cavities will then be overfilled by manufacturer-dictated lubrication. All cavities within the housing tend to fill before grease is forced out of relief fittings normally provided to permit air to escape during grease injection. This excess of grease acts as an insulator, causing the operating temperature of bearings to rise and reducing their service life. Since the relief fittings are conventionally located where they cannot be seen, the operator doesn&#39;t know that the cavities are overfilled. 
     In addition to the aforedescribed problems associated with conventional systems, a substantial amount of grease is required to fill the entire cavity. This increases operation costs. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved bunching saw assembly for a timber harvesting machine. 
     It is another object of the invention to provide an improved lubrication system for the rotating vertical spindle in a bunching saw assembly. 
     It is another object to provide an improved lubrication system wherein a separate lubricant cavity is associated with each of the upper and lower bearings supporting the rotating vertical spindle in a bunching saw assembly. 
     It is another object to provide an improved lubrication system which requires much less lubricant because separate upper and lower bearing cavities, combined, are much smaller than the cavity in conventional assemblies. 
     It is still another object to provide an improved lubrication system wherein each of the separate lubricant cavities encircles the spindle and has an inlet zerk fitting and an outlet vent fitting positioned in such a manner that the presence of lubricating grease at each bearing can positively be confirmed. 
     The foregoing and other object of the present invention are realized in a bunching saw assembly wherein a vertical spindle drives a horizontally oriented saw disc fixed to its lower end. The spindle extends vertically through a saw assembly housing supported by vertically spaced upper and lower bearing sub-assemblies mounted in the housing cavity. A fluid motor seated on top of the housing, over the cavity, is drivingly connected to the spindle. 
     According to the invention, a lower bearing seal is mounted in the housing cavity immediately above the lower bearing sub-assembly. The lower bearing seal is seated on an annular support surface extending around the cavity above this seal. An upper bearing seal is mounted in the housing cavity immediately below the upper bearing sub-assembly. The upper bearing seal is seated on an annular support surface extending around the cavity below this seal. 
     The upper and lower bearing sub-assemblies include bearings which are, accordingly, disposed in separate upper and lower bearing cavities. The upper bearing cavity has a grease inlet passage extending radially outwardly from it, through the housing, above the bearing, and a grease vent passage extending radially outwardly from it, through the housing, below the bearing. The lower bearing cavity has a grease inlet passage extending radially outwardly from it, through the housing, above the bearing, and a grease vent passage extending radially outwardly from it, through the housing, also above the bearing. The inlet and vent passages for the lower bearing cavity are opposite each other relative to the axis of the assembly, i.e., 180° apart. On the other hand, the inlet and vent passages for the upper bearing cavity are displaced only 43° from each other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, including its construction and method of operation, is illustrated more or less diagrammatically in the drawings, in which: 
     FIG. 1 is a side view of a bunching saw attachment on a timber harvesting, feller-buncher machine; 
     FIG. 2 is an enlarged front elevational view of the bunching saw attachment illustrated in FIG. 1; 
     FIG. 3 is a top plan view of the bunching saw attachment illustrated in FIG. 2; 
     FIG. 4 is a top plan view of the saw motor mount and drive shaft bearing housing for the disc saw in the attachment; and 
     FIG. 5 is an enlarged front view, partially in section along line  5 — 5  of FIG. 4, showing the lubrication system of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, and particularly to FIG. 1, a feller buncher machine is shown generally at  10 . The feller buncher machine  10  includes a four-wheel drive tractor  11  having two front wheels  12  and two rear wheels  13 , although it could be a three wheel tractor with only one rear wheel. 
     A bunching saw attachment  16  is mounted on the front end of the tractor  11 , between the front wheels  12 . In operation, the attachment  16  cuts a number of trees, one-by-one, and holds them upright in a bunch as the tractor  11  moves the attachment from tree-to-tree. When a prescribed number of trees have been felled and bunched in this manner, the feller buncher carriers them out of the cutting area and deposits them for subsequent transport. 
     Referring now to FIGS. 2 and 3, the bunching saw attachment  16  is seen to comprise a frame  18  in which a disc saw assembly  20  embodying features of the present invention is mounted. The disc saw assembly  20  is centered in the back of the frame  18 , between a gathering arm arrangement  22  on one side and a severed tree accumulation pocket  25  on the other side. The gathering arm arrangement  22  engages each tree as it is cut and moves the severed tree into the pocket  25 . A bunching arm  27  then engages and holds the severed tree in this position while the gathering arm arrangement  22  pivots back into its open position, to be prepared for the next tree. 
     Referring now also to FIGS. 4 and 5, the rotary disc saw assembly  20  includes a vertically oriented saw housing  30 . The housing  30  contains a vertically oriented spindle  33  which it supports for rotation within the housing on the axis A of the spindle. 
     As seen only in FIG. 5, the spindle  33  is rotated in the housing  30  by a fluid motor  35  mounted on top of the housing and drivingly connected to the spindle. A circular saw disc  36  is mounted on a lower end plate  38  of the spindle  33 . 
     The spindle  33  includes a cylindrical lower section  41  which extends upwardly from the lower end plate  38  of the spindle. The lower end plate  38  is formed unitarily with the spindle  33 . 
     The spindle  33  further includes a tapered intermediate section  44  and a cylindrical upper section  46 , the upper section being of lesser diameter than the lower section  41  and being joined to that lower section by the tapered intermediate section  44 . 
     The upper section  46  of the spindle  33  has an internally splined well  48  formed axially into its free end. An externally splined sleeve  49  is seated in the well  48  and protrudes upwardly, out of the well. 
     The sleeve  49  is also internally splined, at  50 . The splines  50  in the sleeve  49  receive an externally splined output shaft  52  protruding downwardly from the hydraulic motor  35  on the axis A of the spindle  33 . 
     The spindle  33  is supported for rotation in the housing  30  on an upper bearing sub-assembly  53  and a lower bearing sub-assembly  54 . The upper bearing sub-assembly  53  supports the spindle  33  on the upper section  46  of the spindle. The lower bearing sub-assembly  54  supports the spindle  33  on the lower section  41  of the spindle. 
     The saw housing  30  includes a vertically elongated, generally cylindrical body  55  which encloses the intermediate section  44  of the spindle  33 , leaving a tapered cavity  56  between the inside of the body and the spindle. The body  55  is seated on an annular support ring  58 , which is rigidly mounted in the attachment frame  18 . 
     The annular support ring  58  has an annular bearing well  62  formed upwardly into it from its lower face  63 . Seated in the well  62 , from below, is the outer bearing race  66  of the lower bearing sub-assembly  54 . Below the outer bearing race  66 , an annular main housing seal well  67  extends outwardly of the bearing well  62 , immediately above the lower face  63 . A main housing seal  69  is seated in the seal well  67 . The main housing seal is positively retained by a snap ring  70 . 
     Above the outer bearing race  66 , an annular lower bearing seal well  72  is formed around the inside of the ring  58 . An annular lower bearing seal  73  is seated in the well  72 . 
     Snugly fit onto the cylindrical lower section  41  of the spindle  33  is an inner bearing race  76 . The inner bearing race  76  is located on the cylindrical lower section  41  by a spacer ring  77  which spaces the bearing race  76  from the lower end plate  38  of the spindle  33 , and is held in place by the end plate. The ring  77  has an outwardly extending lower lip  79  which underlies the lower bearing seal well  67  when the saw spindle  33  is operatively mounted in the housing  30 . 
     Both the outer bearing race  66  and the inner bearing race  76  are tapered outwardly, from top to bottom, where they oppose each other and seat a series of roller bearings  82  extending around the spindle  33 . The roller bearings  82  form a lower bearing cavity  83  between the bearing races  66  and  76 , and rotate in that cavity. The balance of the cavity  83  is normally filled with lubricating grease. 
     Lubricating grease is injected into the cavity  83  through a zerk port  86  on a radially extending grease passage  87 . The passage  87  opens into the cavity  83  at the inner end of the passage, immediately outward of the lower bearing seal  73 . 
     Opposite the grease passage  87 , i.e., 180° removed therefrom around the support ring  58 , is a grease vent passage  89 . The grease vent passage  89  communicates with the bearing cavity  83  immediately outward of the lower bearing seal  73 . 
     According to the invention, grease is injected into the zerk port  86  until the cavity  83  has filled and grease begins to emerge from the vent passage  89 . The operator then knows the roller bearings  82  are fully lubricated between the races  66  and  76 . The main housing seal  69  prevents the grease from escaping below the bearing sub-assembly  54 . 
     The body  55  of the saw housing  30  has a mounting ring  91  seated on its upper end. The mounting ring  91  is rigidly mounted in the frame  18  and supports the upper end of the housing  30 , as well as serving as an anchor plate for the motor  35 . 
     Seated on top of the mounting ring  91  is a spacer ring  93 . The spacer ring  93  has an internal pilot shoulder  95  formed around its upper surface for receiving a corresponding pilot ring on the bottom of the motor  35 . The spacer ring  93  has an external pilot shoulder  98  formed around its lower surface for seating onto the mounting ring  91 . 
     The body  55  of the housing  30  has an annular shoulder  99  formed in its inner surface immediately below the mounting ring  91 . The outer bearing race  101  of the upper bearing sub-assembly  53  is seated on this shoulder  99 . 
     Snugly fit onto the cylindrical upper section  46  of the spindle  33  is the inner bearing race  103  of the upper bearing sub-assembly  53 . Both these bearing races  101  and  103  are tapered inwardly, from top to bottom, where they oppose each other and seat a series of roller bearings  106  extending around the spindle  33 . 
     The roller bearings form an upper bearing cavity  107  between the bearing races  101  and  103 , and rotate in that cavity. The bearing cavity  107  opens downwardly into an annular grease cavity  108  defined below by an annular seal support ring  110  secured to the inner surface of the body  55  about 0.39 inches below those races. An annular upper bearing seal  112  is mounted between the inner bearing race  103  and the ring  110 , against the outer periphery of the spindle  33 . The ring  110  is spaced 0.39 inches below the shoulder  99  supporting the outer bearing race  101 . 
     The bearing cavity  107  opens upwardly into an annular grease cavity  114  defined above by the inside of the spacer ring  93  and the annular outer surface of a cap nut  116 . The cap nut  116  is internally threaded at  117  so it can be turned onto the externally threaded upper end of the spindle section  46 . 
     The cavities  114 ,  107 ,  108  are filled with grease through a grease inlet zerk port  119  and passage  121  (see FIG.  4 ). The passage  121  extends radially into communication with the cavity  114 . A grease vent passage  123  extends radially out from the cavity  108  below the bearing sub-assembly  53 , displaced only 43° from the grease inlet passage  121  around the axis A of the spindle  33 . 
     According to the invention, grease is injected into the inlet zerk port  119 . It fills the cavity  114  above the roller bearings  106  first, and only then migrates under pressure down through the bearing filled cavity  107  until it fills the cavity  108 . Grease emerging from the vent passage  123  indicates that the roller bearings  106  are fully lubricated. 
     The saw assembly  20  is assembled by press fitting the ring  77  onto the spindle  33  until it seats on plate  38 . The inner bearing race  76 , carrying the bearing rollers  83  and their supporting cage (not shown) is then press fit onto the spindle  33  against the ring  77 . The annular lower bearing seal  73  is then slid down the spindle  33  until it rests on the inner bearing race  76 . 
     The aforedescribed spindle  33  sub-assembly is then inserted upwardly through the housing  30  until the inner race  76  and bearing rollers  82  contact the outer race  66 . The annular upper bearing seal  112  is slid down the spindle  33  until it seats on the support ring  110 . The upper inner bearing race  103  is placed over the spindle  33  and seats against the roller bearings  106  in their cage (not shown) resting on the outer bearing race  101 . 
     The cap nut  116  is then threaded downwardly onto the end of the spindle  33 . The annular lower lip  124  of the cap nut  116  engages the inner bearing race  103  and draws the spindle  33  upwardly through it until only a prescribed amount of endplay is achieved between the lower inner race  76  and the lower outer race  66 . 
     At this point, the internally and externally splined sleeve  49  is slipped into the well  48 , keying the end of the spindle  33  and the cap nut  116  together. This locks cap nut  116  in place and the spindle  33  and housing  30  together. The motor can then be mounted with its splined output shaft  52  extending into the sleeve  49 . 
     The saw assembly  20  is operational after the saw disc  36  is mounted. The saw disc  36  may be mounted after the aforedescribed assembly operations are completed or, in the alternative, the saw disc  36  and spindle  33  can be preassembled. 
     The spindle  33  has been shown and described as tapered in its intermediate section. However, it should be understood that in some embodiments of the invention it may not be tapered. Similarly, the construction and operation of the cap nut  116  might be varied without affecting the lubrication system embodying features of the invention. 
     Lubrication of the upper and lower bearing sub-assemblies  53  and  54  is simple and inexpensive with the lubrication system of the present invention. The system assures positive feedback to the operator on when the bearing sub-assemblies are properly greased. In addition, whereas conventional lubrication systems require 10-30 pumps of grease a day, the present system may use only 2-3 pumps a day. Furthermore, with less grease, bearing operating temperature is lower, resulting in longer bearing life. 
     While a preferred embodiment of the invention has been described, it should be understood that the invention is not so limited, and modifications may be made without departing from the invention. The scope of the invention is defined by the appended claims, and all devices that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.