Abstract:
A boom unit for a tree processing machine having a boom with a square cross-section. The boom unit has a boom support with a front boom mounting at the front end of the support and a rear boom mounting at the rear end of the support. The boom is movably mounted through the front and rear boom mountings and is positioned to have a corner of the boom on the bottom and an opposite corner of the boom on the top directly over the bottom corner. The front mounting has a pair of front, bottom rollers arranged in a v shape to cradle the boom with the bottom corner of the boom between the rollers and a single, top, guide member above the bottom rollers and centered with respect to the bottom rollers to ride on the top corner of the boom to hold the boom against the bottom rollers.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention is directed toward a boom unit used in a tree processor. 
         [0003]    2. Description of the Related Art 
         [0004]    Boom units for tree processors, such as delimbers, are known. The boom unit has a boom movably mounted through a tubular support, the support rotatably and pivotably mountable on a vehicle. The boom is movable through the support to first grip and to then lift and move a cut tree to be held by the support at its cut end. The boom is then moved relative to the support and the held tree to delimb it. The boom is normally rectangular in cross-section with a height greater than its width. The boom rests on a flat, bottom side in the tubular support, the bottom side horizontal. There are boom support means on the support, usually in the form of top, bottom, and side rollers at both ends of the support, between which the boom moves. The top and bottom rollers minimize up and down movement of the boom while the side rollers minimize sideways movement of the boom. Boom moving means, usually in the form of a chain and sprocket drive with the chain mounted on top of the boom, and the sprocket mounted on the support, move the boom forwardly and rearwardly through the support. 
         [0005]    The mounting of the boom in the above manner however results in high maintenance of the unit. The boom, because of the nature of the work, is constantly being forced against the rollers with sideways forces and sudden up and down forces when a tree is gripped and lifted by the boom or when a tree is released by the boom. Each bottom roller is unequally stressed when the boom is forced against either side during use leading to rapid wear and replacement of the bottom rollers. In addition, the chain and sprocket drive used to move the boom through the support is constantly stressed due to lateral movement of the boom and the attached chain relative to the support and attached sprocket and also requires frequent maintenance and replacement. 
         [0006]    In an effort to reduce maintenance, it is known to provide a boom unit having a boom with a square cross-section, the boom mounted through a tubular support and movable through the support in either direction. The support supports the boom with opposed corners of the boom on a vertical center line so that one corner of the boom is at the bottom center of the boom. Such a boom is shown in U.S. Pat. No. 3,735,786 issued May 29, 1973 to Rudy Vit. The support is constructed with four walls defining a tube with a square cross-section and positioned to support the boom with a boom corner at the bottom. Rollers are mounted in all four walls of the support at its front and rear ends to movably support the boom for movement through the support and to minimize movement of the boom both up and down and sideways in the support. The mounting the boom on a corner, rather than on a side, centers the boom on the two bottom rollers at the front and rear of the support. When the boom is extended relative to the support and picks up a tree, the load is transferred to the bottom, front rollers and the top, rear rollers of the support. Mounting the boom in the above manner, where it is cradled between the bottom rollers, equalizes the load between the bottom rollers and reduces maintenance compared to the maintenance required by booms with a rectangular cross-section mounted on a narrow side. 
         [0007]    However, the arrangement of using a boom with a square cross-section, the boom mounted on a corner, still requires frequent maintenance. The system uses a relatively large number of rollers all of which require servicing. The front, top and rear, bottom rollers, while not load bearing to the same extent as the front, bottom and rear, top rollers, are unequally affected by sideways and up and down movements of the boom during use. Also, all the rollers are each mounted with a pin supported by bushings and roller bearings at each end. Replacement of any roller and/or the bearings is difficult. In addition, a drive means other than a chain and sprocket drive is required to move a boom mounted on a corner and the different drive means used is quite complicated. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    It is the purpose of the present invention to provide a boom unit for a tree processor having a boom support, and a boom of square cross-section movable through the support and supported thereby with two opposed corners of the boom on a vertical center line of the boom, which unit is simpler in construction, holds the boom more securely, and is easier to maintain and service. It is another purpose of the present invention to provide a boom unit as described with boom moving means for moving the boom relative to the boom support which moving means are simple in construction, easy to service, and reliable in use. 
         [0009]    In accordance with the present invention a boom unit for a tree processor is provided with a boom having a square cross section. The boom is mounted through a boom support with two opposed corners of the boom on a central vertical line and one of the opposed corners at the bottom of the support. In accordance with the present invention, the boom support has a frame carrying front and rear boom mounting means thereon. The front boom mounting means has a pair of front, bottom rollers mounted on the front of a frame, and the rear boom mounting means has a pair of rear, top rollers mounted on the rear of the frame. The front rollers are arranged to form a v-shaped support for the boom supporting the boom by its two bottom sides. The rear rollers form an inverted v-shape support for receiving the two top sides of the boom. The frame also supports a top, front guide member, as part of the front boom mounting means, overlying the bottom, front rollers. The top, front guide member bears on the top corner of the boom. The frame further carries a bottom, rear guide member, forming a part of the rear boom mounting means, under the top, rear rollers for supporting the boom by its bottom corner. The front bottom and rear top rollers hold the boom securely against lateral movement while the front, top and rear bottom guide members co-operate with the front and rear rollers to hold the boom against any vertical backlash during operation. The mounting arrangement more securely holds the boom during its operation against vertical and lateral movement using fewer moving parts than known arrangements. 
         [0010]    In accordance with the present invention, the front, bottom and rear top rollers are mounted on cantilevered spindles. The spindles allow the use of tapered bearings and a simple nut and washer connection to hold the rollers in place on the spindles. The rollers and/or the bearings can be easily replaced using a spindle mounting. 
         [0011]    The present invention also provides a simple boom moving means for moving the boom relative to the boom support. The boom moving means can comprise a cable for moving the boom. The cable is generally mounted above the boom with the ends of the cable attached to the boom support, the cable passing over cable guide means at the ends of the boom. The cable passes through a cable drive mounted on the boom support. 
         [0012]    The invention is particularly directed toward a boom unit for a tree processing machine, the boom unit having a boom with a square cross-section and a boom support for the boom. Front and rear boom mounting means are provided at the front and rear ends of the boom support. The boom is movably mounted through the boom mounting means, the boom positioned to have two opposed corners on a vertical center line with one of the opposed corners at the bottom of the boom. The front boom mounting means has a pair of front, bottom rollers in a v-shape to cradle the boom and a single, front, top guide member above the bottom rollers and centered with respect to the bottom rollers to ride on the top corner of the boom to hold the boom against the bottom rollers. 
         [0013]    The invention is also particularly directed toward a boom unit for a tree processing machine having a boom with a square cross-section and a boom support for the boom. Boom mounting means are provided at the front and rear ends of the boom support. The boom is movably mounted through the boom mounting means, the boom positioned to have two opposed corners on a vertical center line with one of the opposed corners at the bottom of the boom. Boom moving means are provided for moving the boom relative to the boom support. The boom moving means has a cable generally mounted above the boom with the ends of the cable attached to the boom support, the cable passing over cable guide means at the ends of the boom. The cable passes above the boom support through a cable drive mounted on the boom support. 
     
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]      FIG. 1  is a side view of a tree processor carrying the boom unit; 
           [0015]      FIG. 2  is a detail side view of the cable drive; 
           [0016]      FIG. 3  is a cross-section view taken along line  3 - 3  in  FIG. 1 ; 
           [0017]      FIG. 4  is a cross-section view of a support roller mounted on a spindle; 
           [0018]      FIG. 5  is a cross-section view taken along line  5 - 5  in  FIG. 1 ; 
           [0019]      FIG. 6  is a side view of a modified boom unit; 
           [0020]      FIG. 7  is a partial cutaway detail side view of the boom unit in  FIG. 6  showing the second cable connection; 
           [0021]      FIG. 8  is a cross-section view taken along line  8 - 8  in  FIG. 6 , but without showing the cable drive; and 
           [0022]      FIG. 9  is a cross-section view taken along line  9 - 9  in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    The boom unit  1  of the present invention, as shown in  FIG. 1 , is usually employed on a tree processor such as a delimber  3 . The delimber  3  has a vehicle  5  with a cab  7  and a rigid, vertical extending, boom unit support arm  9 . The support arm  9 , and cab  7 , are mounted for rotation about a vertical axis on the vehicle  5 . The support arm  9  has the boom unit  1  at its top end. The boom unit  1  comprises an elongate boom  13  and a boom support  15 . The boom support  15  has front and back boom mounting means  17 ,  19  at its front and back ends  21 ,  23  through which the boom  13  is mounted for movement relative to the support  15 . The boom unit  1  is mounted on the end of the support arm  9  by a horizontal pivot  25  connecting the support arm  9  and the support  15 . A hydraulic cylinder  27  is pivotably mounted between the support arm  9  and the support  15  to tilt or pivot the boom unit  1  relative to the support arm  9  about the pivot  25 . 
         [0024]    The boom  13  has a tree processing head  29  at its front end. The tree processing head  29  carries tree gripping means  31 , and tree cutting means  33 , if needed. Tree gripping means  35  are mounted on the boom support  15  at its front, bottom end, the gripping means  35  aligned with the tree gripping means  31  on the head  29  on the boom  13 . The boom  13  grasps a cut tree with its gripping means  31  and positions the butt end of the cut tree in the tree gripping means  35  on the support  15 . The boom is then moved to have its gripping means  31  delimb the held tree while supporting it. 
         [0025]    Boom moving means  37  are carried by the boom unit  1 . The boom moving means  37  include a cable drive  39  mounted on top of the support  15 . The cable drive  39 , as shown in detail in  FIGS. 2 and 3 , has a fixed, generally rectangular, platform  41  on top of the support  15 . A movable, generally rectangular, platform  43  is pivotably mounted at about the middle of its long sides, via pivots  45 , on the fixed platform  41 , the movable platform  43  generally overlying the fixed platform  41 . The pivot axis  47  is transverse to the boom  13 . Shock absorbing means  49  in the form of springs, or other suitable cushioning means, are mounted between the fixed platform  41  and the movable platform  43  at the front and the rear of the platforms. The cable drive  39  has a drive pulley  53  and first and second central guide pulleys  55 ,  57  one on each side, and adjacent to, the drive pulley  53 , mounted between support brackets  59  on the movable platform  43 . The cable drive includes a radial piston type hydraulic motor  60  to selectively rotate the drive pulley  53  in either direction. 
         [0026]    The boom moving means  37  includes a rear support post  61  mounted on the back of the boom  13 , the post  61  carrying a rear guide pulley  63 . A front guide pulley  65  is attached a front support post  67  on the top front of the boom  13 . A drive cable  69  moves the boom  13  relative to the support  15 . The drive cable  69  is attached at one end to the front end  21  of the support  15  as shown at  71  and extends forwardly from the support  15 , under and over the front guide pulley  65  and back to the cable drive  39 . The cable  69  passes under the first central guide pulley  55 , over and around the drive pulley  53 , and under the second central guide pulley  57 , back over the rear guide pulley  63  and to the back end  23  of the support  15  where its other end is attached as shown at  73 . Rotation of the drive pulley  53  in either direction by the motor  60  will move the boom  13  in either direction relative to the support  15  via the cable  69 . The central guide pulleys  55 ,  57  hold the cable  69  frictionally tight about the drive pulley  53  to have the drive pulley  53  move the cable  69  in either direction as it rotates in either direction. The shock absorbing means  49  between the fixed platform  41  and the movable platform  43  absorb any backlash from the cable  69  when the boom  13  is stopped moving in either direction thereby extending the life of the cable  69 . 
         [0027]    The boom  13  has a square cross-section and is mounted on the support  15  with one corner  79  on the bottom and the opposite corner  81  on the top, as shown in  FIG. 3 , the corners aligned on the vertical center line  83  of the boom  13 . The bottom corner  79  is formed by the joint between the two adjacent bottom walls  85 ,  87  of the boom and the top corner  81  is formed by the joint between the two adjacent top walls  89 ,  91  of the boom. 
         [0028]    The support  15  has a main bottom frame  93  which frame can be in the form of a length of inverted angle iron. The frame  93  is connected to a base  95  to which the support arm  9 , the hydraulic cylinder  27  and the tree gripping means  35  are attached. The front boom mounting means  17 , shown in  FIGS. 1 and 3 , is mounted at the front of the frame  93  and has a pair of front, main, support arms  97 ,  99  extending upwardly and outwardly from the bottom frame  93  away from each other. The main support arms  97 ,  99  are at 90° to each other, each arm at 45° to the vertical. A pair of front, secondary, support arms  101 ,  103  extend transversely from the outer ends of the main support arms  97 ,  99  upwardly and inwardly toward each other to join above the center of the bottom frame  93 . The secondary support arms  101 ,  103  are also at 90° to each other. A pair of front, bottom, rollers  105 ,  107  are mounted on the inside of the main support arms  97 ,  99 . The rollers  105 ,  107  extend at  900  to each other and form a ‘v’. A front, top, guide member  109  is mounted from the secondary support arms  101 ,  103 , to be centrally located over the frame  93 . The guide member  109  can comprise a wheel rotatable about a horizontal axis which axis is transverse to the longitudinal axis of the frame  93 . The periphery of the wheel  109  has a v-shaped groove  111  to receive the top corner  81  of the boom  13 . 
         [0029]    In more detail, as shown in  FIG. 4 , the bottom rollers  105 ,  107  are each mounted in cantilever fashion on the main support arms  97 ,  99 . Since the mounting for both rollers is the same only one will be described in detail. Roller  107  is mounted on a spindle  113 , which in turn is mounted at one end to a bracket  115  on support arm  99  near its bottom end. The spindle  113  extends upwardly and outwardly from the bracket  115  parallel to the support arm  99  but a bit above it. The spindle  113  is stepped adjacent to the bracket  115  as shown at  117  and receives the tubular roller  107  thereon. The roller  107  carries tapered bearings  119 ,  121  at each end  123 . The ends  123  of the roller  105  are tapered to receive and position the bearings  119 ,  121 . The lower bearing  119  bears against the step  117  on the spindle  113  to locate the bearings and roller on the spindle. The end  125  of the spindle  113  projecting from the roller  105  is threaded and a washer  127  and nut  129  are attached to the threaded end  125  of the spindle  113  to hold the roller  105  and bearings  119 ,  121  in place. It will be seen that the roller  105  and the tapered bearings  119 ,  121  can be easily removed and replaced due to the cantilevered mounting. 
         [0030]    The rear boom mounting means  19 , as shown in  FIGS. 1 and 5 , are at the rear of the frame  93  and comprise a pair of rear, main, support arms  133 ,  135  extending outwardly and upwardly from the bottom frame  93  away from each other. The rear, main support arms  133 ,  135  are at 90° to each other, each arm at 45° to the vertical. A pair of rear, secondary, support arms  137 ,  139  extend transversely from the ends of the rear, main, support arms  133 ,  135  upwardly and inwardly to be joined at the top over the main frame  93 . The rear, secondary support arms  137 ,  139  are also at 90° to each other. A pair of rear, top, rollers  141 ,  143  are mounted on the secondary rear support arms  137 ,  139 , the rollers extending at 90° to each other and forming an inverted ‘v’. The rollers  141 ,  143  are mounted in cantilevered fashion on spindles  145  connected at one end to brackets  147 , which are in turn mounted to the secondary support arms  137 ,  139 . The rollers  141 ,  143  are mounted on the spindles  145  in the same manner that the front bottom rollers are mounted on the spindles. A rear, bottom, guide member  151  is mounted over the center of the frame  93 . The guide member  151  can comprise a wheel rotatable about a horizontal axis which axis is transverse to the longitudinal axis of the frame  93 . The rear guide wheel  151  also has a v-shaped groove  153  on its periphery to receive the bottom corner  81  of the boom  13 . 
         [0031]    The front and rear boom mounting means  17 ,  19  are dimensioned to have the boom  13  pass through them securely held against lateral movement between the rollers  105 ,  107  and guide wheel  109  at the front boom mounting means  17 , and the rollers  141 ,  143  and guide wheel  151  at the rear mounting means  19 , while allowing the boom to move longitudinally relative to the support  15 . The front mounting means  17  supports the boom  13 , via its bottom walls  85 ,  87  resting on the front, bottom rollers  105 ,  107  with the front, top guide wheel  109  riding on the top corner  81  of the boom. The rear mounting means  19  supports the boom  13  with the bottom corner  79  of the boom  13  riding on the rear, bottom, guide wheel  151  and the rear, top, rollers  141 ,  143  riding on the top walls  89 ,  91  of the boom. 
         [0032]    The boom mounting means are simple yet provide good support for the boom. When the boom  13  picks up a tree, the boom is forced down against the front mounting means  17  to bear equally against the front bottom rollers  105 ,  107 , centering the boom against the rollers. Equal weight is placed on both rollers resulting in equal wear. The front, top, guide wheel  109  prevents the boom  13  from moving up away from the front, bottom rollers  105 ,  107 . While the boom is forced down against the front mounting means, its rear portion is forced up against the rear mounting means  19  to bear equally against the rear top rollers  141 ,  143  again resulting in equal wear on the rear rollers. The bottom corner  79  of the boom is centered on the rear, bottom, guide wheel  151  maintaining the boom against the rear rollers  141 ,  143  to center its top corner  81  between the rollers. The mounting means  17 ,  19  together prevent top and sideways movement of the boom during operation. If needed, the top and bottom guide wheels  109 ,  151  can be adjustably mounted on the support to allow the guide wheels to be adjusted toward or away from their respective bottom and top rollers so as to firmly hold the boom while still allowing it free movement through the support  15 . 
         [0033]    The design of the boom mounting means allows the rollers and wheels to be easily serviced and replaced. The design also better controls backlash movement of the boom both laterally and vertically during operation thus increasing the life of the boom mounting means. Having the boom guiding rollers angled allows the use of tapered bearings for mounting the rollers, which in turn makes replacement of the bearings easier. In the standard arrangement, where a boom of rectangular cross-section rides on a bottom wall, the bearings are press fit roller bearings and replacement is more difficult. The roller mounting of this invention, cantilevered on a spindle, allows the use of tapered bearings making installation and replacement of the bearings much easier. The mounting also allows the bearings to operate in a bath of oil or grease increasing the life of the bearings. 
         [0034]    The support  15  is reinforced with horizontal framing members  157  extending between the outer ends of the front, main, support arms  97 ,  99  and rear, main, support arms  133 ,  135  and between the outer ends of the front secondary support arms  101 ,  103  and the rear secondary support arms  137 ,  139 . The support  15  can be enclosed if desired with panel members (not shown) mounted on the framing members  157  and the bottom frame member  73  forming a tubular support. The ends of the support  15  are left open allowing the boom to pass through the support and more particularly through the front and rear boom mounting means  17 ,  19 . The cable drive  39  is mounted on the horizontal framing members  157  via the fixed platform  41 . 
         [0035]    The boom unit  1  has been described with a boom  13  consisting of a single boom member. The boom unit  1  could also have a telescopic boom  209  having an outer boom member  211  and an inner boom member  213  telescoped within the outer boom member  211  as shown in  FIGS. 6 to 9 . Both boom members  211 ,  213  have a square cross-section and are positioned within the support  15  on the boom unit  1  with the outer boom member  211  having a bottom corner  215  and an opposed top corner  217  on a vertical center line  219  of the boom  209  as shown in  FIG. 8 . The inner boom member  213  also has a bottom corner  219  and an opposed top corner  221  on the vertical center line  219 , the bottom corner  219  of the inner boom member  213  adjacent the bottom corner  215  of the outer boom member  211 . The inner boom member  213  can move relative to the outer boom member  211  to lengthen or shorten the boom  209 . Rollers (not shown) could be provided at the outer end  221  of the outer boom member  211  and at the inner end  223  of the inner boom member  213  to allow the boom members to move more freely relative to one another. 
         [0036]    The outer boom member  211  is mounted through the support  15 , its bottom walls  225 ,  227 , bearing against the bottom rollers  105 ,  107  of the front boom mounting means  17  and its top walls  229 ,  231  bearing against the top rollers  141 ,  143  of the rear boom mounting means  19 . The bottom corner  215  of the outer boom member  211  rides on the rear, bottom, guide wheel  151  while its top corner  217  rides against the top, front, guide wheel  109 . 
         [0037]    Using a telescopic boom  209 , the boom moving means  37 ′ would be modified to have the front guide pulley eliminated and to use a second cable. The front end of the first cable  69  is now attached at  233  to the processing head  29  which head is now carried by the inner boom member  213  at its front end. The first cable  69 , as before, extends back to the cable drive  39 . The cable  69  passes over the first central guide pulley  55 , under and around the drive pulley  53 , up and over the rear central guide pulley  57 , back over the rear guide pulley  63  and to the back end  23  of the support  15  where its other end is attached as shown at  73 . 
         [0038]    A second cable  235  is attached to the front end of the support  15  as shown at  237  and extends forwardly to pass over a guide pulley  239  attached to the front end  221  of the outer boom member  211  and back to be attached at  241  to the rear end  223  of the inner boom member  213  as shown in  FIG. 7 . The arrangement allows the first cable  69  to pull the inner boom member  213 , and thus the processing head  29 , rearwardly. As this happens, the second cable  235  pulls the outer boom member  211  rearwardly. When the cable  69  is pulled in the other direction, the movement of the outer boom member  211  forwardly causes second cable  235  to pull the inner boom member  213  forwardly relative to the outer boom member  211 .