This invention relates to a method of and grab apparatus for tree removal.

This invention has particular but not exclusive application to removing single live trees from the ground by use of grab or grabhoo apparatus and for illustrative purposes, reference will be made to such method. However, it is to be understood that this invention may be useful for removing stumps of trees, or removing in-ground poles or posts or such like. For illustrative purposes the apparatus of this invention is described with reference to being mounted on the end of the jib or dipper arm of a mechanical hoe or excavator and reference hereinafter will be made to such application. However, the apparatus of this invention could be used in other applications, such as application using specialised machinery or equipment. Moreover, the apparatus of this invention may be used in other applications such as materials handling of elongated or generally round objects such as logs, boulders, pipes or other goods or for material handling purposes.

In the felling or harvesting of timber, the trees are cut down leaving a stump behind. Frequently, harvesters are provided for felling the timber, however stump removal often represents a problem for re-use of the forest land, such as for replanting or reforestation. Stumps are often difficult to remove and the removal involves an extra, costly and time consuming step.

Additionally, machinery used for harvesting timber is ineffective for other purposes, such as tree lopping, as the exposed hydraulic power lines may net be visible to the operator and are often fouled and damaged by the adjacent branches. Tree felling machinery is usually ineffective for tree stump removal as there is insufficient trunk available

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for grasping by the apparatus. Moreover, such apparatus is not suitable for use in general material handling applications.

In clearing land of timber using conventional methods, there is considerable environmental damage due to the kwlldσzing of trees from the ground. Not only is the sσ±l considerably disturbed, but undergrowth is almost destroyed by such practices. Additionally, watercourses are fouled by sediment, and silting of streams results from undesirable erosion of the land. Similar problems are encountered in thinning a forest for controlling or enhancing the growth of a crop timber.

Prior art methods of uprooting trees have required shaking of the tree and moving the tree away from its vertical axis in a manner which requires the root ball of the tree to be moved horizontally through the ground, presenting a difficulty in constructing apparatus to perform such a method. Additionally, trees may be removed in areas having containing overhead power lines. In such locations, removal of a tree in one piece may cause the top portion of the tree to contact or fouling the overhead power lines.

Furthermore, when there is an appreciable wind force on a tree, clearing or felling is usually abandoned because of lack of control of the tree once it is severed from its trunk or from the ground. Moreover, tree manipulation machinery is generally not suitable for use on rough or precipitous terrain.

The present invention aims to alleviate at least one of the above disadvantages and to provide a method of, and grab apparatus for, removing a tree and/or tree stumps which will be reliable and efficient in use.

This invention in one aspect resides broadly in grab apparatus engageable with a portion of an elongate article intermediate its ends, said grab apparatus including:-

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a claw assembly having two or more spaced claw members adapted to partly encircle an elongate article; a movable jaw assembly for operatively closing said claw assembly and having one or more jaw members; drive means for selectively moving said movable jaw assembly towards and away front said claw sseHfWy, and mounting means enabling said grab apparatus to be mounted for pivotal movement about an axis normal to an elongate articled operatively engaged between said claw assembly and said jaw assembly.

The grab apparatus may be mounted on machinery adapted to position the grab apparatus to a desired location. Preferably, the mounting means is a mounting cooperable with a jib boom and crowd arm assembly of an excavator. The grab apparatus is preferably engageable with the jib or dipper arm of the mechanical excavator and the mounting means is pivotally engaged with the distal end mount of the dipper arm whereby pivoting of the grab apparatus is provided by engaging the mounting means with a crowd arm typically provided on mechanical excavators. The engagement may be direct or by way of through a typical quick-hitch arrangement frequently provided on such excavators.

The jaw assembly may be mounted for translatory movement to and from the claw assembly but preferably the jaw assembly is pivotally mounted on the mounting means. The claw assembly preferably includes a partly encircling inner bearing surface against which an article to be grabbed may be held and the jaw assembly includes a distal end part remote from a pivotal mounting for pivotally moving the movable jaw assembly towards and away from the claw assembly such that the distal end part passes adjacent the inner bearing surface during the pivotal movement.

The distal end part may pass within a small clearance from the bearing surface, or may pass within a groove or

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channel provided within the bearing surface adapted to accommodate the distal end part. Thus, the bearing surface preferably includes a concavity so formed and arranged that the pivotal movement of the jaw assembly permits the distal end part to pass at least partly within the concavity. Where ^• cie concavity os provided in tire rrm of a g oeytna or- channel a respective groove is associated with each claw member.

Alternatively, the concavity may be interposed between respective the claw members and operatively associated with a respective jaw member operable to close between two claw members. The jaw members are preferably more than one in number and more preferably, there are two jaw members. Preferably, each jaw member is pivotable about a common axis and the end portions of each claw member are equidistant from the axis.

It is also preferred that the claw assembly includes a base portion and a distal portion remote from the base portion such that the jaw assembly is operable with the base portion and the distal portion to captively encircle an object to be grabbed.

The grab apparatus also includes a lower edge and is mounted on the jib boom of an excavator such that the pivotal movement of the grab apparatus is substantially at the lower edge. The pivotal movement at the lower edge is preferably about an axis normal to an elongate articled operatively engaged between the claw assembly and the jaw assembly.

It is also preferred in such arrangement that the jaw members move to an open position towards the side of the grab apparatus visible to the operator. This invention also envisages that these features could also be applied to conventional grabbers to enhance their versatility. Such modification constitutes another aspect of this invention.

Additionally, one or more of the fixed claw members and associated jaw members may be provided with resilient

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engagement means for resiliently engaging with the surface of the tree being grabbed. Where there are two sets of respective jaw member and claw member assemblies, it is preferred that the upper set is provided with the resilient engagement means, such as a rubber, elastomer or such like lining, about the inner periphery of tire jrespe rtl—ts f r member and claw member for contact with the surface of the tree or object.

It is also preferred that the lower set is provided with narrower lands or a larger area ram for contact with the tree such that greater compression of the tree is possible whereby the upper portion of the tree is more easily broken from the remainder of the tree during that part of the operation. In an alternative form, the upper and lower sets of jaw and claw members are provided with controls which may be selectively separated or joined whereby individual actuation and pressure may be applied to the individual sets, or at an operator's selection, the operation of both sets is effected together with equal operating force. The lower set of jaw and claw members may also be so formed and arranged as to enhance the severing ability of the lower set, such as a scissor arrangement between the jaw and claw members, sharpened edges, or such like. Alternatively, a cutting assembly may be provided separately as described elsewhere herein. Additionally, gripping barbs, spikes, sprogs or such like may be provided on the inner surfaces of the jaw and claw members for gripping the tree.

It is also preferred that the distal ends of the claw members and the jaw members are provided with tine means to enable the grab apparatus to be used for minor ground or earth movement. In particular, where the grab apparatus is to be used on steep inclines, the tine means may be used to loosen the soil and arrange is such as, for example, to form a platform suitable for the excavator upon which the grab

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apparatus is mounted. The platform may be formed so that it is substantially horizontal such that the excavator may more safe and stable from capsizing.

Moreover, the tine means may be used to permit at least some of the grab apparatus to penetrate the soil in the case of removal of a tree stump which has little or no trunk portion extending above the ground surface.

The drive means may take the form of electric or internal combustion motors or such like. Preferably, the drive means includes hydraulic drive means for moving the jaw assembly and pressure control means for limiting pressure applied thereto.

It is also preferred that the hydraulic drive means includes feed means, such as hydraulic hoses or the like, for feeding hydraulic pressure to the jaw assembly and the feed means which is visible to an operator of the grab apparatus in order that the operator may avoid damaging or fouling the feed means. Alternatively, the feed means is located internally of the jib boom or the like. The hydraulic drive means includes hydraulic ram means which may be adapted for moving the each jaw member independently. Preferably, however, the hydraulic ram means is adapted to provide substantially equal clamping pressure to each jaw member. Additionally, the hydraulic drive means may include pressure control means for limiting the pressure applied to the jaw members for example, for grabbing smaller timber sections.

Additionally, the grab apparatus may be provided with cutting means such as a chain or disk saw assembly for cutting material being grabbed by the grab apparatus.

Suitably, the cutting means is driven by drive means and the cutting means is retractable whereby an object held by the grab apparatus may be cut by the cutting means, and the cutting means is operable towards the side of the grab

apparatus visible to the operator.

Thus, hydraulic controls for the apparatus and the cutting means are all provided towards one side of the dipper arm so that an operator can see whether hydraulic lines are being fouled and/or damaged by material being targeted for treatment of the like by the grab apparatus as well as observe the operation of the cutting means.

Additionally, the grab apparatus may be provided with spray means for applying a liquid from the grab apparatus in the form of a jet or spray. For example, where regrowth from root portions of a tree left in the ground is likely, a herbicidal liquid spray may be applied from the spray means.

Moreover, where the area to be cleared is environmentally sensitive, or where adjacent plants are to be retained, or in windy conditions, a spray containment assembly is provided. For example, a conical or covered cylindrical housing may be provided, and may be adapted to be grabbed by the grab apparatus and be so formed and arranged that spray from the spray means may be sprayed into the interior or the housing, but the housing may be put aside for the tree removal operation.

The spray means may be attached to the underside of the grab apparatus, or may be located within the grab apparatus, or on the distal end of the jib. Alternatively, a separate spray and containment assembly may be provided as a separate unit to follow behind the excavator upon which the grab apparatus is mounted.

In another aspect, this invention resides broadly in a method for removing a tree from the ground, including:- providing a mechanical harvester having a tree grab formed with pivot means for pivoting the tree grab about a substantially horizontal axis adjacent the base of the tree and lifting means for lifting the tree grab; grabbing the tree to be removed adjacent its base;

pivoting the tree grab to cause the tree to tilt about its base and to disturb the ground about the tree roots, and elevating the tree grab to lift the tree from the ground. Preferably, the tree is pivoted away from the mechanical harvester through an angle of approximately 20°. It is further preferred that the mechanical harvester is operated to simultaneously tilt and lift the grabbed tree.

Preferably, the grab apparatus is operated to forcibly pivot the tree trunk about a substantially horizontal axis at or close to the ground surface and forcibly lift the tree trunk to free the tree together with the root mass at its base. If desired, the stump may be cut or severed from the stem of the tree after it has been lifted from the ground but prior to the tree being released from the grab apparatus. For example, where the tree has a tap root, the tap root may be fractured by tilting the tree prior to lifting to lessen the force required to lift the tree from the ground. For trees having fibrous root systems, tilting the tree at the same time as lifting enables the uprooting force to be concentrated to a portion of the root ball.

If desired, the stumps and tree stems from trees removed from the ground in accordance with the method of this invention may be placed in two separate respective groups, or in respective receptacles such as truck wagons or dumpsters or such like.

In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate typical preferred embodiments of the invention and wherein:- Figure 1 is a view of the side, top and rear of a grab apparatus;

Figure 2 is a view of the side, top and rear of an alternative grab apparatus;

Figure 3 is a side elevation of the grab apparatus shown

in Figures 1 and 2, with the attachment bracket removed;

Figure 4 is sectional plan view from above of the grab apparatus shown in Figure 3 taken on line A-A;

Figure 5 is sectional plan view from above of the grab apparatus shown in Figure 3 taken on line B-B;

Figure 6 is an isometric view of a grab apparatus in use for grabbing a cylindrical object;

Figure 7 is a side elevation of a grab apparatus in an alternative connection to a mechanical excavator; Figure 8 is a diagrammatic side view of a mechanical excavator with a grab apparatus operatively connected to the jib and in use to grab a tree;

Figure 9 is a diagrammatic side view of the mechanical excavator and grab apparatus of Figure 8 with the grabbed tree removed from the ground, and

Figure 10 is a diagrammatic side view of the mechanical excavator and grab apparatus of Figure 8 in use to break out the upper portion of a tree.

Referring to Figures 1, a grab apparatus 10 includes a body portion 11 which has extending therefrom two claw assemblies 13. Two corresponding jaw assemblies 12 are hingedly attached to the body portion 11 with mounting pins (now shown) provided through two pairs of respective jaw mounting apertures 16. The respective jaw assemblies 12 may move in the direction of an arrow 52 towards or away from the body portion 11. This hinged movement is effected by two respective rams, only one of which is shown diagrammatically at 14, the respective rams 14 being mounted onto the body portion 11 through respective mounting pins (not shown) extending through two pairs of respective ram mounting apertures 15 on the body portion 11. The rams 14 extend to be connected to the jaw assemblies by two pairs of ram arm connection apertures 33, one respective pair being provided

on each jaw assembly 12.

The body portion 11 and claw assembly 13 is constructed by forming four substantially identical claw plates 23. The two upper claw plates 23 are separated by respective claw webs 24 and respective ram enclosure webs 28 as are the two lower claw plates 23. The upper and lower pairs of claw plates 23 are separated by a main body casing 25 and a main casing continuation 39.

The proximal end of each jaw assembly 12 is enclosed by a ram enclosure casing 31 and a windowed web 32, the ram 14 passing through a ram arm window 41. In Figures 1 and 2, part of the ram enclosure casing 31 has been removed.

Additionally, the inner pair of claw plates 23 are separated from one another by a main body bearing web 38. The upwardly facing claw plates 23 are also provided with an inspection aperture 35 as shown.

The grab apparatus 10 is mounted on the jib and crowd- arm assembly of an excavator by a mounting assembly 19. The mounting assembly 19 includes two jib brackets 21 and two crowd-arm brackets 22 (only one of which is shown) which respective apertures for receiving mounting pins for connection to a typical quick hitch assembly or such like. The mounting assembly 19 is attached to the body portion 11 by two adjustment plates 17 (only one of which is shown), the relative position of the mounting assembly being adjustable by attachment to selected mounting apertures shown typically at 18.

Each jaw assembly 12 includes two jaw plates 27 each separated by a jaw web 26. Additionally, each claw assembly 13 and jaw assembly 12 is provided on its respective distal end with a tine member 30 which may be removed and replaced as required.

Referring to Figure 2, an alternative grab apparatus 20 is substantially identical to the grab apparatus 10 shown in

Figure 1, with the exception that an alternative mounting assembly 29 is provided, being connected to the adjustment plate 17 through respective mounting apertures 18 in a similar manner. Like elements in the alternative grab apparatus 10 are given the same reference numerals as the grab apparatus 10 described with reference to Figure 1.

Referring to Figures 3, 4 and 5, the grab apparatus 10 or the alternative grab apparatus 20 is shown without the respective mounting assembly 19 or alternative mounting assembly 29.

Referring to Figure 4 in particular, the jaw assembly 12 further includes two jaw web supports 36 extending radially away from the jaw web 26, and the jaw assembly 12 and claw assembly 13 each include a tine support 37 onto which is mounted the respective tine members 30.

It is to be noted that the jaw assembly 12 in Figures 4 and 5 is shown in a closed position, the jaw web 26 closing to be closely parallel to a closure web 34 provided on the main body portion 11. The tine member 30 associated with the jaw assembly 12 passes between the respective claw plates 23 as shown.

Referring to Figure 5 in particular, it can be seen that the main body portion 11 and claw assembly 13 when taken together and are constructed of two box sections comprised of the respective claw plates 23 connected by the main body casing 28 which forms a box section with the main body bearing web 38 and one of the adjustment plates 17, and another box section being comprised of the main casing continuation 39, the other adjustment plate 17 and another portion of the main body bearing web 38.

Referring to Figure 6 in particular, a log or pole 42 may be grabbed by the grab apparatus 10 or 20 as shown. If desired, the log or pole 42 may be severed beneath the grab apparatus 10 or 20 if an optional saw assembly is provided.

The saw assembly 40, if provided, is preferably arranged to be retractable beneath the main body portion 11.

Referring to Figure 7 in particular, the grab apparatus 10 or 20 may be oriented with the tine members 30 in a downward orientation for moving soil or the like. This may be useful if a level platform needs to be constructed for resting an excavator upon for safe working.

Referring to Figure 8, an excavator 50 is shown fitted with the grab assembly 10 or 20 on a jib 46 and a crowd arm 47 so that the grab assembly 10 or 20 has its pivotable jaws 12 visible from a control cab 44. Thus, the grab assembly 10 or 20 may be used to remove a tree 45 as shown in particular in Figure 9 according to the method of this invention. Referring to Figure 10, the excavator 50 and grab apparatus 10 or 20 may be used to remove the upper portion 53 from the trunk 49 of the tree 45 as shown. Subsequently, the upper portion 53 is laid aside and the trunk portion 49 is removed by the method of this invention in a similar manner to that shown in respect of Figure 9. In use, the grab apparatus may be used to remove a tree from the ground by locating the claw members against the tree at or near to the ground surface, closing the jaw members against the tree, pivoting the grab apparatus with the crowd ram on the excavator, the direction of pivoting being away from the excavator, in order to break the major roots and/or loosen the root system of the tree from the soil, the tree being pivoted away from its upright attitude. In a preferred mode of operation, it has been found that for large trees, it has been found that it is efficacious to remove the tree by first pivoting it away from the excavator to 70" from a horizontal ground surface, then pivoting the tree back to 110" from the same surface, then back to substantially upright for lifting.

A lifting force is preferably applied with the pivoting

action, or alternatively, the tree is pivoted back to a substantially upright attitude and simultaneously or immediately thereafter lifted out of the ground with the grab apparatus on the end of the mechanical excavator by manipulating the dipper arm, the crane boom and/or main boom of the excavator.

Once the tree has been removed, it may be laid on the ground for retrieval in a subsequent operation, or placed into a bin, hopper, truck or trailer for the purpose of removal of the tree from the site. Quite small sections may be grabbed by the grab apparatus by closing the jaw members against the small section, with the distal ends of the jaw members able to sweep through the internal channel provided in the claw members. The mounting means for the grab apparatus preferably permits the grab apparatus to be mounted with the claw members above the jaw members such that the grab apparatus may be used for grabbing horizontal elongate objects.

Additionally, the grab apparatus may be used to trim standing trees by reaching up into the foliage and grabbing a branch and removing it as required. For example, where a "cherry picker" device is often used, with its risks of personal injury, the grab apparatus of the present invention may be used to prevent or remove arboreal fouling of power or communications lines, or for trimming plants for aesthetic purposes.

It has also be surprisingly found that in uprooting trees under power lines, undergrowth remains substantially intact or with little damage. It is predicted that regrowth or regeneration of the undergrowth is thus enhanced which may decrease the rate of regrowth of trees. Thus, after several clearances, low shrubbery may predominate and decrease the requirement for further deforestation in such areas as power line corridors.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as claimed in the following claims.