Abstract:
The multifunction brush cutter head attachment is versatile and designed for forestry operations, ground preparation for tree plantation, side road maintenance and other areas where precise cleaning of brushes and small trees is required. The invention consists of rotary shafts cutters as a cutting means to chop the brushes and small trees into wood chips or log sections. The steel welded frame of the invention includes two large opening ports on each side to avoid machine jams. The invention can reach hidden parts behind objects using a rotational system mounted on the top of the frame. Lengthways knives are secured with wedge blocks on the rotary shafts cutters and are easily removable for sharpening or maintenance. As the rotary shafts cutters have a low moment of inertia, the invention requires little power and is particularly suitable for small size excavator.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    Not-applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED R&amp;D  
       [0002]    Not-applicable 
       REFERENCE TO SEQUENCE LISTING . . . APPENDIX  
       [0003]    Not-applicable 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    The invention relates to a brush cleaning equipment that can be installed on the working boom of a small excavator. The described equipment can be used for trimming areas of undergrowth, shrubs and small trees. 
         [0006]    2. Description of the Prior Art 
         [0007]    Forestry operations, ground preparation for tree plantation and side road maintenance are all different areas where brush cleaning is required regularly. These operations can be done with manual brush cutting equipments but this way, the productivity is usually very low and operator&#39;s safety is a matter of concern. The introduction of mechanical brush cutting equipments improved productivity and safety in a significant way. 
         [0008]    From the prior art, it can be found that there are two different groups of mechanical brush cutting equipment. One group refers to machines totally dedicated to brush cutting and not designed for other uses. The second group refers to mechanical working head equipments attached to a mechanical boom. This invention is related to the second group, the mechanical working head attachment equipment. The following patents are also associated to working head attachment for brush cutting operation. 
         [0009]    U.S. Pat. No. 5,042,727 describes a brush cutting head attachment, using a plurality of cutting blades mounted on a vertical shaft. It operates in a limited vertical movement and is not designed for horizontally work as required for cleaning brushwood under larger trees. 
         [0010]    U.S. Pat. No. 5,408,814 describes a brush cutter head attachment using a circular cutting blade to cut brushes. The attachment can cut trees into different lengths as well as chopping brushes into small chips. 
         [0011]    U.S. Pat. No. 6,311,746 consists in an arrangement of four circular saws in a row. The brush cutting attachment can operate under any angle from horizontal to vertical. The group of circular saws is mounted on a same rail and can slide inside or outside to reach a larger field. The major inconvenient of this invention is related to the difficulty of chopping wood into small wood chips. Consequently, this brings extra cost to eliminate the wood residues left on the site. 
         [0012]    U.S. Pat. No. 6,764,035 describes a brush cutter head attachment using several discs mounted on a horizontal main shaft to cut the brushes. Each disc has a plurality of cutting teeth that cut and chop the bushes to small chips. The movement of the equipment is mainly vertical but it can also work under large trees. As several discs are mounted on the main shaft, due to the high moment of inertia, it requires high torque and high power as used on large excavators which that are more expensive to acquire and to operate. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention offers a different kind of brush cutting equipment for cutting and chopping brushes, undergrowth, shrubs and small trees. 
         [0014]    Therefore, an object of the present invention is to provide an attachment that can be used in several forestry operations rather than one or two with other attachments. The forestry operations are described as followed:
       a) small trees felling: by cutting the tree stump and leaving the tree on site;   b) trees or brushes chopping: to reduce the tree or the brushes into small wood chips left on the site for soil enrichment;   c) small trees harvesting: by cutting wood in different lengths.   d) small trees trimming: by cutting the trees boughs for growing purpose.       
 
         [0019]    More particularly, the present invention relates to a multifunction brush cutter head to be installed at the tip end of a small excavator working boom and comprising:
       a) a rigid steel welded frame with two large open ports on each side;   b) perpendicular to the open ports, a plurality of rotating grooved shafts cutter where lengthways knives are inserted and secured;   c) a motorization to put the shafts in rotation;   d) a mechanical rotation system to operate the said brush cutter head in several positions.       
 
         [0024]    Therewith, an aspect of the present invention is a steel welded frame with a front plate and a back plate. Another bent plate makes the top shielding and half length sides over the rotating shafts. Behind the back plate, there is an end plate welded with sides to the back plate that form a hollow section to hold the pulleys and belts drive of the motorization. Therefore, large open ports are at the bottom of the attachment. This design is highly efficient to avoid machine jams. The design of the steel welded frame offers the possibility to cut brushes in a forward mode, a backward mode and sideways mode because there is no definite entrance and exit ways. In fact, in the forward mode the working boom and the multifunction brush cutter head is pushed ahead through the brushes up to the full extension length of the boom. Then, the said boom is brought back in the backward mode and brushes will still be cut. This increases by double the productivity of the operation. The boom operating sequence of forward and backward or sideways action can be associated to a double pass action. This way of working is more efficient compared to many other brush cutter equipments that can only work under a single pass forward action. 
         [0025]    Another particularity of the present invention is the small diameter of the rotating shafts cutters. In comparison with cutting wheel and sawing blade, rotating shafts cutters have a lower moment of inertia requiring less power to put the said shafts in motion as well as to stop them. Several brush cutting equipment have big shafts cutter 6 to 8 inches (0.1524 m to 0.2032 m) diameter. With such diameters, the moment of inertia is about 1408 lb.in 2  to 4453 lb.in 2  (0.412 kg.m 2  to 1.303 kg.m 2 ) using the standard formula I=(Mr 2 )/2 for a solid cylinder rotating on its longitudinal axe where I is the moment of inertia and M is the mass of the shaft (we assume a length of 39 inches and a shaft made of steel as example to calculate the mass) and r is the radius of the shaft. With the present invention, the rotary shafts cutter diameter is lower than 3 inches (0.0762 m) and the moment of inertia is therefore 89 lb.in 2  (0.026 kg.m 2 ). Also with three rotary shafts cutters, the total moment of inertia is about 267 lb.in 2  (0.078 kg.m 2 ). The lower moment of inertia allows the installation of the present invention on small excavator with an operating weight less than 10 tons rather than other brush cutting equipments that are installed on bigger excavators with an operating weight from 10 to 20 tons. 
         [0026]    Rotating shafts cutters are also best suited for chipping the brushes because the cutting action is similar to wood planing. Rotary shafts cutters are also different from cutter wheels and sawing blades as they stand in place by the ends and not by the center. 
         [0027]    Another object of the present invention is to use a motorization to put the rotating shafts in motion. The motor is preferably hydraulic but it can also be electric. When a hydraulic motor is used, the pressure oil is supplied by the hydraulic system of the excavator. The power from the motor can be transferred to the rotating shafts cutters by the use of pulleys with belts or sprockets with chain or by the use of gears train. Belt drives are preferred as they offer a mechanical shock dampener for the motor. Another embodiment of the motorization unit is the use of direct drive motors. In such case, each rotating shaft cutters have their own motor. 
         [0028]    Another particularity of the invention is the mechanical rotation system of the head. The rotational system is mounted on the top of the frame and attached to the boom of the excavator. This embodiment enhances the operating potential of the multifunction brush cutter head. In fact, the mechanical rotation system offers the possibility to surround an object with little or any movement of the excavator supporting the brush cutting head. The rotation system allows a rotating action up to 300 degrees of the applicant brush cutter and therefore raises the working capacity in different sites. 
         [0029]    Finally, another particularity of the present invention is an attachment for quick releasable coupling of the multifunction brush cutting head with the working boom of the excavator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a general view of a small excavator with the brush cutting head in a typical working environment. 
           [0031]      FIG. 2  shows the operating option of the present invention to clean brushes around larger trees with the rotational system without moving the excavator on the soil. 
           [0032]      FIGS. 3 ,  4 ,  5  &amp;  6  are respective views of the brush cutting head uses for tree felling, trimming, rough cleaning, and fine cleaning with wood chipping operation. 
           [0033]      FIG. 7  is a view of the single head model of the invention. 
           [0034]      FIG. 8  is a view of the double head model of the invention. 
           [0035]      FIG. 9  illustrates a side view of the single head model of the invention. 
           [0036]      FIGS. 10 ,  11  &amp;  12  illustrate cross-section views taken along line  10 - 10  in  FIG. 9  showing different embodiments of the rotary shafts cutter. 
           [0037]      FIG. 13  illustrates a cross-section view taken along line  13 - 13  in  FIG. 9  showing the rotary shafts cutter and the knives. 
           [0038]      FIG. 14  illustrates a cross-section view taken along line  14 - 14  in  FIG. 9  showing the mechanical rotation system. 
           [0039]      FIG. 15  illustrates an explode view of the head with the motor and the driving system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0040]      FIG. 1  illustrates a typical working area for the present invention. A small excavator  1  actuates a working boom  2  to which the multifunction brush cutter head  3  is attached. The said brush cutter has several rotary cutter shafts  4  that will chop the brushes  5  to smaller twigs  6 . The multifunction brush cutter head  3  also has a mechanical rotating system  9 . The mechanical rotation system  9  is bolted on the top of the brush cutter head  3 . The mechanical rotation system  9  has a welded attachment  29  with bore holes to lock it to the tip end of the working boom  2  and to the hydraulic cylinder  30  by the use of a locking device like shaft pins. As illustrated in  FIG. 1  a typical working area may include larger trees  7 , brushes  5  and undergrowth  8 . Thereby, cleaning operation will require cutting undesirable vegetation close to the larger tree  7 . 
         [0041]      FIG. 2  illustrates a top view of preferred working embodiments associated with the present invention. The small excavator  1  is in front of a tree  10  and brushes around must be cut. With the present invention it is possible to surround the tree  10  and to cut brushes aside and behind it. Furthermore, the brush cutting operation aside and behind the tree  10  does not require moving the small excavator  1  avoiding roots and soil compaction and increasing operation productivity. As shown in  FIG. 2 , the mechanical rotation system  9  allows the rotating action of the multifunction brush cutter head  3 . Also shown in  FIG. 2 , the present brush cutter head  3  may rotate up to 150 degrees on both left and right hand sides around a tree, a post or any permanent object. Also in  FIG. 2 , the phantom lines  92  show the position that the multifunction brush cutter head  3  can take without moving the excavator  1  by moving only the working boom  2  and rotate the mechanical rotation system  9  to reach brushes behind the tree  10 . 
         [0042]      FIGS. 3 ,  4 ,  5  &amp;  6  illustrate other preferred working embodiments of the present invention. 
         [0043]      FIG. 3  illustrates the operation of small tree felling where the tree stump  11  is cut. The tree boughs  12  can be chopped before or after the felling operation. Also valuable sections of the small tree might be used in further wood transformation. 
         [0044]      FIG. 4  illustrates the tree boughs trimming operation in a typical tree plantation. In this kind of operation the excavator  1  and the multifunction brush cutter head  3  should preferably be between two rows of trees  14  and  15  (only the first tree of the row is showed to simplify the drawing). The said brush cutter head  3  will be pivoted to face the tree row. Tree trimming will be performed by moving the working boom  2  and the brush cutter head  3  from top to bottom and by the reversed sequence bottom to top to trim the boughs  13 . Using the mechanical rotation system  9  the multifunction brush head  3  can trim the left and the right hand side trees without moving the excavator  1  which increases the productivity. 
         [0045]      FIG. 5  illustrates a rough cleaning operation (for example) through brushes  16 ,  17  and  18 . The brush cutter head  3  is showed without the excavator. In this kind of operation the multifunction brush cutter head  3  starts from the far left hand side for example and at the top of the brushes  16 . By moving the working boom  2  (not shown) and the brush cutter head  3  to the far right hand side in order to follow the pattern  19 , a layer of brushes  16 ,  17  and  18  will be cut. By lowering the working boom  2  (not shown) to the middle height of the brushes  18  and by moving the brush cutter head  3  to the far left hand side another layer of brushes  18 ,  17  and  16  will be cut. By repeating the above sequence once again for the lowest layer of brushes the rough cleaning operation will be completed. Brushes  16 ,  17  and  18  are chopped into small wood chips and long wood strips. 
         [0046]      FIG. 6  illustrates a fine cleaning and chopping operation (for example) through brushes  16 ,  17  and  18 . The operation sequence is similar to the one described in  FIG. 5  with the following difference: the operator will start from the far left hand side for example and at the top of the brushes  16 . By moving the working boom  2  (not shown) and the brush cutter head  3  to the far right hand side to follow the pattern  20 , a layer of brushes  16 , 17  and  18  will be cut. The said brush cutter head  3  will then be lowered to an approximate distance equivalent to half the height of the brush cutter head  3 . By moving the brush cutter head  3  to the far left hand side and therefore, another layer of brushes  18 ,  17  and  16  will be cut. This operation will generate small wood chips which are sometimes requested for cleaning operation close to power lines and side road maintenance. 
         [0047]    The preferred embodiment of the present invention is illustrated in  FIG. 7  where the multifunction brush cutter head  3  has a rectangular steel welded frame. The steel welded frame has a front plate  21 , a back plate  22  and an end plate  23 . The front plate  21  is a pseudo rectangular flat plate forms by narrower up section with a surrounding flat edge strip  24 . The back plate  22  and the end plate  23  have the same shape as the front plate  21  and are welded with a side plate  25  near and around the edges of said plates to form a hollow section holding the pulleys and belts drive of the motor. The steel welded frame has also a top shielding  26 . The top shielding  26  is a bent plate that also forms the half sides of the frame over the rotating shafts cutter  4 . Over the shielding top  26 , there is another bent plate  27  with a hinge cover  28 . The top shielding  26  and bent plate  27  are welded between the front plate  21  and the back plate  22 . The multifunction brush cutter head  3  also has rotary shafts cutters  4  between the front plate  21  and back plate  22 . The main action of the rotary shafts cutter is to chop the brushes and undergrowth into small wood chips and twigs. As the multifunction brush cutter head might have only one rotary shaft cutter, it may also have several and the preferred embodiment is an arrangement of three as detailed in  FIG. 7 . 
         [0048]    A second embodiment of the present invention is the double head brush cutter  31 , only illustrated in  FIG. 8 . This embodiment contributes to double the productivity with the same motorization on larger ground areas. The double head brush cutter  31  is a single head brush cutter as described in  FIG. 7  with more rotary shafts cutter  4   b  located symmetrically behind the endplate  23 . The said double head has a longer rectangular steel welded frame. The steel welded frame has a two front plate  21  and  21   b,  a back plate  22  and an end plate  23 . The front plates  21  and  21   b  are a pseudo rectangular flat plate forms by narrower up section with two surrounding flat edge strip  24  and  24   b.  The back plate  22  and the end plate  23  have the same shape as the front plate  21  and are welded with a side plate  25  near and around the edges of said plates to form a hollow section holding the pulleys and belt drives of the motor. The steel welded frame has also two top shielding  26  and  26   b.  The top shielding  26  is over the rotary shafts cutter  4  and the top shielding  26   b  is over the rotary shafts cutter  4   b.  The top shielding  26  and  26   b  are bent plates that also form the half sides of the frame over the rotating shafts cutter  4  and  4   b.  Over the shielding top  26  and  26   b,  there are two bent plates  27  and  27   b  with two hinge covers  28  and  28   b.  The top shielding  26  and bent plate  27  are welded between the front plate  21  and the back plate  22 . The top shielding  26   b  and bent plate  27   b  are welded between the front plate  21   b  and end plate  23 . 
         [0049]      FIG. 9  illustrates a side view of multifunction brush cutter head  3  to show the line  10 - 10 ,  13 - 13  and  14 - 14  of cross-sectional views described in  FIGS. 10 to 14 . 
         [0050]      FIG. 10  illustrates a cross-section view taken along line  10 - 10  in  FIG. 9 . It was previously said, that the multifunction brush cutter head  3  can have one rotary shaft cutter  4  or several but the preferred embodiment is an arrangement of three as shown. 
         [0051]      FIG. 11  illustrates a cross-section view taken along line  10 - 10  in  FIG. 9 . to show an alternate embodiment with two rotary shafts cutters  4 . 
         [0052]      FIG. 12  illustrates a cross-section view taken along line  10 - 10  in  FIG. 9 . to show an alternate embodiment with four rotary shaft cutter  4 . 
         [0053]      FIG. 13  illustrates a cross-section view taken along line  13 - 13  in  FIG. 9 . to show the details of how the knives are secured to the rotary shaft cutters  4 . The central portion  32  is a round shaft machined to receive the knives  33  with sharpens edges  34 , the wedges  35  and the compression bolts  36 . The knives  33  are secured to the central portion  32  with a wedge  35  designed to take on the exact shape in the central portion  32  and when the compression bolts  36  are tightened, the wedges taper sides  37  push against the knives  33  and hold them firmly in place. The compression bolts  36  are hollow hexagonal head bolts (Allen bolts) seating in a bore hole  38  drilled and bored through the wedges  35 . 
         [0054]      FIG. 14  illustrates a cross-section view taken along line  14 - 14  in  FIG. 9  to show the mechanical rotation system  9 . This system allows lateral rotation movement of the multifunction brush cutter head  3  up to 300 degrees. The casing  43  of the mechanical rotation system is bolted on the top of the frame of brush cutter head  3 . A hydraulic motor  39  is used to rotate the drive shaft  40  held in place in the casing  43  with two bearings  44   a  and  44   b.  On the drive shaft  40 , there is a worm screw  41  that put the worm gear  42  in rotation around the bearing unit  45 . The worm gear  42  is bolted under the welded attachment  29  (not shown) itself locked on the tip end of the working boom  2  (not shown) and to the hydraulic cylinder  30  (not shown). The bolts of the worm gear  42 , the welded attachment  29 , the working boom  2  and the hydraulic cylinder  30  have been previously showed in a side view in  FIG. 9 . 
         [0055]      FIG. 15  illustrates a detailed exploded view of the brush cutter head  3  (only one rotary shaft cutters is shown and every bolts and has been removed to simplify the drawing). The front plate  21  has bore holes at the bottom to support the rotary shafts cutter  4 . In the preferred embodiment there are three bore holes  46  (one shown, two hidden) arranged like a triangular pattern. In each of the bore holes a front hub  47  is used to support the front end  53  of the rotary cutter shafts  4 . Each front hub  47  has a spherical roller bearing  49 , a shaft seal  48 , a snap-ring  50  (also called “circlip”, this fastener consists in a sprung ring with open ends that can be snapped into a machined groove to allows rotation but to prevent lateral movement) and an end cover  51 . The front hub  47  is bolted to the front plate  21 . Lubrication fluid is added to the bearing by a greasing point  52  screwed on the end cover  51 . The back plate  22  also has bore holes at the bottom arranged in the same triangular pattern as in the front plate  21 . In each of the bore holes a back hub  57  is used to support the back end  55  of the rotary shaft cutters  4 . Each back hub  57  has a spherical roller bearing  59 , a shaft seal  58 , a first snap-ring  60 , a ball bearing  61  and a second snap-ring  62 . The back hub  57  is bolted to the back plate  22 . Lubrication fluid is added to the bearings by a greasing point  63  screwed on the back hub  57 . The spherical roller bearing  59  allows rotation between the back end  55  of the rotary shaft cutters  4  and the fixed end hub  57 . The ball bearing  61  allows rotation between the toothed pulley  64  and the fixed end hub  57 . 
         [0056]    The end section  56  of the rotary shaft cutters  4  has outer machined spline grooves thus inserted in the inner machined spline grooves of toothed pulley  64  to have a good mechanical link when the toothed pulley  64  is in rotation. 
         [0057]    The three toothed pulleys  64  must be supported on the other side by end hubs  68  that are similar to the back hubs  57 . Each back hub  68  (one shown, two hidden) is bolted in the bore hole  67  of the support plate  65  attached to the back plate  22  with four bolts that goes through four hollow rods  66 . Each back hub  68  has a spherical roller bearing  70 , a shaft seal  69 , a first snap-ring  71 , a ball bearing  72  and a second snap-ring  73 . Lubri-cation fluid is added to the bearings by a greasing point  74  screwed on the back hub  68 . 
         [0058]    The three toothed pulleys  64  get in rotation with two toothed belts  87  and  88 . The toothed pulley  80  drives the central toothed pulleys  64  with first toothed belt  88 . The toothed pulley  80  drives the two other lower toothed pulleys  64  with the second toothed belt  87 . The driving toothed pulley  80  is supported by two bearings in a tightening device which includes: a flange plate  84 , a roller bearing  83 , a main plate  81 , a roller bearing  79  a bearing holder  77  and an end cover  76 . The end cover  76  is bolted to the bearing holder  77 . The bearing holder  77  is bolted on the hollow rod  78  welded on the main plate  81 . The flange plate  84  is bolted on the main plate  81 . The main plate  81  of the tightening device is mounted by the hole  82  and bolted on a pivot pin (not shown) welded on the back plate  22 . A bolt (not shown) located on the other side of the back plate  22  allows to block the tightening device when the belts tension is adequate. 
         [0059]    The hydraulic motor  85  is bolted on the flange plate  84  and the motor&#39;s shaft  86  has outer machined spline grooves thus inserted in the inner machined spline grooves of driving toothed pulley  80 . This kind of assemblage ensures a good power transmission from motor  85  to the rotary shafts cutters  4 . Also the hydraulic motor  85  is protected and located inside the compartment formed by the top shielding  26 , the bent plate  27 , the hinge cover  28 , the front plate  21  and the back plate  22 . The hydraulic hoses (not shown) are connected from the motor  85  to the hydraulic ports  91  for quick coupling purpose. The end plate  23  is welded on the side plate  25 . There are two openings  89  and  90  to make maintenance of components easier. Those openings have bolted covers (not shown) during normal operation of the brush cutter head. 
       Front Page View 
       [0060]    Use  FIG. 1  for inclusion on the front page of the patent application and patent as the illustration of the invention.