Abstract:
A shear type tree cutter assembly is adapted to be mounted on a four wheel field vehicle. The assembly includes an anvil with a concave section for supporting the trunk of a tree. The blade portion has a convex portion that cooperates with the concave section of the anvil to shear the tree. The blade and anvil section also may include a straight portion useful for pruning brush and small limbs.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     This invention is a shear type tree cutter that is in the form of an attachment to a four wheel multipurpose field vehicle such as a Bobcat® or a four wheel front loader, for example. The shear tree cutter can easily be adapted to be attached to the coupling devices of skid loaders and front end tractor loaders. The attachment is capable of cutting down trees up to about six inches in diameter with a high degree of reliability and effectiveness at a relatively low cost. 
     2. Description of Related Art 
     Tree shearers are known in the prior art such as the one described in U.S. Pat. No. 5,503,201. This device utilizes two pivoted straight edge blades mounted on an attachment adapted to be coupled to a variety of different forms of front loader vehicles. U.S. Pat. No. 6,662,836 B1 discloses a tree shear attachment that includes a single straight blade that pivots toward a stationary straight jaw 92. The patent to Wildley U.S. Pat. No. 4,221,245 discloses a convex blade 23 moving toward indentation 50. For trees larger than 8″ or more, Wildey uses a pivoted chain saw 24 to sever the tree. 
     BRIEF SUMMARY OF THE INVENTION 
     Applicant&#39;s invention resides in providing a rugged, extremely reliable shear type tree cutter that is capable of successfully cutting trees of larger diameter than similarly sized tree shears. This results in less down time for repairs. The invention also includes the ability to replace the cutting blade should it wear out. An additional aspect of the invention is the provision of a smaller pruning type cutting surface on the end of the blade for snipping off smaller trees and branches. The improved cutting capability is achieved by the unique shape of the shear blade and shearing anvil along with strategically positioned reinforcement members. 
     In another aspect of the invention, when the device is coupled to a front loader, a swivel mechanism can be provided to allow the tree cutter to be pivoted so that it can be used to trim branches from trees. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  is a perspective view of the tree cutter coupled to a front loader tractor. 
         FIG. 2  is a perspective view of the tree cutter. 
         FIG. 3  is a top view of the tree cutter attachment. 
         FIG. 4  is a top view of a portion of the tree cutter attachment with the cutting blade in a retracted position. 
         FIG. 5  is an exploded view of the various parts of the tree cutter. 
         FIG. 6  is a perspective view of an alternative coupling for the attachment. 
     
    
    
     The drawings provided herein are meant to illustrate the principles of the invention in general terms and are not intended to limit the invention to the specific details shown in the drawings. Other shapes and sizes for the various structural members could be used without departing from the invention, which is set forth in the accompanying claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1 , the shear tree cutter assembly  7  is adapted to be mounted on a front loading tractor  1  via a coupling frame  5 . The frame  5  has upper and lower support beams  15  and  13 , vertical end support members  17  and  19  and intermediate vertical support members  21  and  23 . 
     A support plate  11  is fixed between vertical support members  21  and  23  by any suitable means such as welding. Mounting tabs (not shown) are positioned on the rear side of the frame  5  for attachment to the forks  3  of the tractor. A first hollow cylindrical member  25  is fixed to the plate  11  and a plurality of triangular reinforcing members  9  extend between the plate and the cylindrical member  25 . Cylindrical member  25  includes two diagonally opposite apertures that receive pin  29 . 
     The tree cutter attachment as shown in  FIG. 2  includes a horizontally extending main support beam  33  which may be any suitable shape such as rectangular or square. Other configurations are also possible. Extending rearwardly of the beam is a stabilizing reinforcing plate  49 . Extending forwardly from the beam  33  is an anvil plate  35  and a vertically extending reinforcing gusset plate  37  that is secured to the anvil plate  35  and beam  33 . Anvil plate includes a concave surface  67  that supports the tree against lateral movement as the blade cuts through the tree. At its outer end the surface  67  includes a straight portion  69  that cooperates with a straight surface  71  on the blade. 
     A vertically extending support member  31  is rigidly secured to the beam  33 . A hollow cylindrical tube  27  with an outside diameter slightly smaller than the inside diameter of cylinder  25  extends rearwardly from the support member  31 . It includes a plurality of diagonally located pairs of apertures that can be aligned with the diagonal apertures in cylinder  25  so that the tube can be rotated and locked by pin  29  in a plurality of angular positions. In this manner, the tree cutter assembly  7  can be rotated about a horizontal axis that extends through cylinders  27  and  25 . A lower pivot pin support plate  61  extends forwardly of the support member  31 . A pair of triangular reinforcing plates  59  is provided between the lower plate  61  and support member  31 . A circular collar  30  is secured to tube  27  and abuts against cylinder  25 . Tube  27  extends through support plate  11  and a similar collar  30  is secured to a portion of the tube that extends beyond the support plate. 
     The cutting blade assembly as shown in  FIG. 5  includes a cutting blade  39  having a convex surface in a horizontal plane and a beveled portion  73  from the top to the bottom surface. An aperture  93  is provided through the blade. The assembly also includes a blade support member  71  having an aperture  91  and a three sided reinforcement member  41 . A lug  77  extends outwardly from reinforcement member  41 . Cutting blade  39  and blade support member  71  are detachably secured to each other with a plurality of threaded bolts  51 . 
     As can be seen in  FIG. 5 , the cutting blade assembly  71  and  39  is pivotably mounted to the device by a support plate  61  and a portion of the anvil at aperture  95 . Pin  53  slides through apertures  99 ,  91 ,  93  and  95  to rotatably support the blade assembly on the beam  33  and vertical support  31 . Apertures  99  and  91  may be provided with hardened bushings so that pin  53  will experience any deterioration first and may simply be replaced. This arrangement provides an extremely rugged and reliable support for the blade. 
     A hydraulic power cylinder  45  has its base end pivotally connected to an angle support plate  47  that is rigidly attached to the support beam  33 . The rod portion  43  of the hydraulic cylinder is pivotably connected to lug  77  of the cutter blade assembly at  65 . Hydraulic lines (not shown) are connected to the hydraulic cylinder  45  as is known in the art to extend and retract rod  43 . Thus blade  39  can be rotated about pin  53 . In the fully extended position, blade  39  extends over the top surface of anvil  35  for about one inch. 
       FIG. 6  illustrates an alternate embodiment of the coupling structure that is specially adapted for use with the coupling structure known as Rapidlink™ used for attaching accessories to Bobcat® utility vehicles. The connection  6  consists of a generally trapezoidal frame with apertures on either side. The frame is adapted to receive a trapezoidal shaped connection plate and locking rod that is mounted on the utility vehicle. 
     Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.