wheel carried truck 30 carries a boom - mounted , tree felling head 32 , constructed in accordance with the invention . pivoted boom 34 is hydraulically controlled by an operator in the truck cabin 36 , via hydraulic lines operating ram means 38 , 40 , 41 in a conventional fashion , wherein head 32 is movable at least along elevational and azimuthal directions and about roll and pitch axes . a floating arm 43 pivoted to boom 34 pivotally interconnects outer end rams 40 and 41 . truck 30 is specifically adapted to circulate over the ground g of a forest made of a plurality of ground standing trees 42 , such as 42a , 42b , 42c , . . . each tree having numerous transverse limbs 44 . all this is known . the felling head of the invention , 32 , consists of a main rigid frame 46 , carried by boom 34 via a pivot mount 48 . the frame 46 itself carries : a pair of ground skimming , coacting jaw members 50a , 50b ; intermediate , coacting , tree grabbing arm members 52a , 52b ; and an intermediate tree retaining lever member 54 . preferably , the top end of chassis 46 carries an upright stay 56 , for abuttingly transversely supporting an upstanding felled tree section thereagainst . more particularly , in the operative , upstanding position of head 32 illustrated in fig1 main frame 46 consists of a front wall 46a , rear wall 46b , two spaced side walls 46c and 46d , and top and bottom ends 46e and 46f . the rear wall 46a is upwardly forwardly inclined relative to the front wall 46a . parallel cylindrical axles 58 , 60 are anchored to each outer side wall 46c , 46d respectively spaced therefrom by brackets 62 and 64 . axles 58 and 60 are substantially parallel to front and side walls 46a - 46c . as shown in fig2 - 3 , grabber arm 52a is pivotally freely carried by axle 58 , while grabber arm 52b and retaining lever 54 are both pivotally freely carried by a single axle 60 . bracket 62 includes an integral seat 62a , freely supporting the pivoted end of grabber arm 52a , at an upper position ( i . e . toward the casing top end 46e ), while bracket 64 includes intermediate and lower integral seats 64a and 64b , freely supporting the pivoted end of retaining lever 54 below the horizontal plane intersecting upper grabber arm 52a and of lower grabber arm 52b below the horizontal plane intersecting the retaining lever 54 ( when viewed in fig1 ). as illustrated in fig5 - 7a , each grabber arm 52a , 52b is rigid , arcuate , defining a free end tip 52a &# 39 ;, 52b &# 39 ;, and an inner end tip 52a &# 34 ;, 52b &# 34 ;, with the respective pivot mount 58 / 60 intermediate tips 52a &# 39 ;/ 52b &# 39 ; and 52a &# 34 ;/ 52b &# 34 ; but proximate the latter tips . a hydraulic ram 66 operatively pivotally interconnects the grabber arm inner tip 52a &# 34 ; to the opposite grabber pivot axle 60 , while a second hydraulic ram 68 operatively pivotally interconnects the other grabber inner tip 52b &# 34 ; to the opposite grabber pivot axle 58 . rams 66 , 68 extend through a free passage 69 made transversely of casing 46 through apertures in side walls 46c , 46d . as illustrated in fig9 - 9a and 10 , retainer member 54 is made of two endwisely pivotally interconnected legs 70 , 72 with inner leg 70 defining an inner tip 70 &# 39 ; and an outer tip 70 &# 34 ; connected to leg 72 by pivot axle 74 . pivot axle 60 freely extends through a section of inner leg 70 intermediate tips 70 &# 34 ; and 70 &# 39 ; proximate the latter , axle 60 being parallel to pivot axle 74 . outer leg 72 includes an edgewise flange 76 having a seat portion 76a extending beyond pivot 74 so as to define a limit position where inner leg 70 abuts against seat 76a when legs 70 and 72 are substantially orthogonal . accordingly , outer leg 72 can pivot freely from its said limit position , up to a quarter of a turn where it will abut against leg 72 in substantially parallel fashion . however , outer leg 72 is biased to its limit position ( orthogonal to leg 70 as shown in fig9 ) by a biasing means 78 . for example , biasing means 78 will be an elastic rubber band ( fig1 ), fixedly endwisely anchored to the interior faces of the flange 76 and leg 70 at two spaced positions intermediate pivots 60 and 74 , by transverse pins 79a and 79b , respectively . preferably , each leg 70 , 72 is made of two elongated spacedly interconnected plates 70a , 70b and 72a , 72b with leg 70 narrower than leg 72 so that the outer end of the former can fit within the hollow of the latter &# 39 ; s inner end , as in fig1 . hydraulic ram 80 operatively pivotally interconnects tip 70 &# 39 ; to main pivot axle 58 . hence , pivot axles 58 , 60 define a common vertical plane , on the one &# 34 ; outer &# 34 ; side of which the standing trees 42 are to engage the felling head front wall 46a , and on the &# 34 ; inner &# 34 ; side of which the pivoted end 70 &# 39 ; of the tree retainer lever 54 is movable between an inoperative tree loading position , in which pivoted end 70 &# 39 ; is located between the vertical planes passing through the pivot axles 58 , 60 orthogonal to their said common vertical plane , to a tree retaining position , in which pivoted end 70 &# 39 ; is located substantially beyond said vertical plane of pivot axle 60 and orthogonal to said common plane of pivot axles 58 - 60 . hence , upper grabber arm 52a , intermediate retainer lever 54 and lower grabber arm 52b , are pivotally movable within three parallel , horizontal planes , independently from one another , under power from ram means 66 , 68 and 80 . ram means 66 . 68 are designed to be operated concurrently . preferably , a tree support plate 82 is transversely anchored to frame 46 , and extends forwardly of front wall 46a being located between upper grabber arm 52a and intermediate lever 54 . plate 82 has a large arcuate notch 84 provided at its inner edge section with edgewise serrated teeth 84a . teeth 84a are designed to tangentially grip a tree 42 having engaged head 32 , i . e . engaged closely to but spacedly from front wall 46a . accordingly , the tree section to be cut is to be captured by arm 54 for bringing the tree section within an area circumscribed by arcuate edge 84 on one side and arcuate arms 70 , 72 of arm member 54 on the other end . as illustrated in fig1 - 14 , jaw members 50a , 50b each consists of a semi - circular disc portion 86 , defining an arcuate edge section 86a and a straight edge section 86b . straight edge 86b is bevelled and sharpened , to constitute a knife for compressingly cutting through a section of tree 42 . accordingly , jaw members 50a , 50b and especially straight edge sections 86b , must be of a very strong material , e . g . tempered steel . two arcuate legs 88a , 88b pivotally interconnect the bottom end section 46f of main feller head frame 46 to the arcuate edge section 86a of flat jaw members 50a , 50b , respectively , about pivot axle 90 . axle 90 is a bolt extending completely through the body of casing 46 , being anchored by large nuts 87 ( fig1 ) to two front and rear wall sections 46g and 46h respectively of frame 46 , these two latter wall sections being parallel to one another and being approximately at a 45 degree angle relative to the plane of front and rear walls 46a and 46b . transverse trusses 85a , 85b reinforce the frame structure by interconnecting walls 46a , 46b and 46f of the unit main frame 46 . axle 90 extends along a forwardly upwardly inclined direction , relative to the vertical front wall 46a . accordingly , jaw members 50a , 50b are pivotally movable from a first limit position , where both knives 86b edgewisely abut one another along a common horizontal plane ( fig1 and 11 ) to a second limit position , where the disc portions 86 of the jaws 50a , 50b are spaced apart from one another and upwardly outwardly inclined along two planes substantially at right angle to one another ( fig1 a and 15 ). hydraulic rams 92 , 94 power operate jaws 50a , 50b . ram 92 is pivotally connected at one end 96 to a pivotwise extension 88b &# 39 ; of jaw leg 88b , and at the other end to an ear 98 radially outwardly protruding from the base of leg 88b ; while ram 94 is pivotally connected at one end 100 to a pivotwise extension 88a &# 39 ; of jaw leg 88a , and at the other end to an ear 102 radially outwardly protruding from the base of leg 88a , hence , when knives 86b edgewisely close on each other , rams 92 , 94 should be substantially parallel to one another and vertical , to provide maximum tangential effort about the orthogonal plane of horizontal disc 86 . preferably , as illustrated in fig1 , the upwardly extending legs 88a , 88b of jaws 50a , 50b are pivotally engaged by pivot axle 90 in the following fashion : a thicknesswise aperture 104 is made into the inner end section 88a &# 39 ; of arm 88a , through which freely extends a diametrally smaller inner end section 88b &# 39 ; of the second arm 88b . a through - bore 106 , 108 is made into inner end sections 88a &# 39 ;, 88b &# 39 ; respectively , for through engagement by axle 90 . profitably , as shown in fig1 , the bottom end of casing 46 carries a further abutment plate 89 with a large notch 89a provided with plurality of serrations again for tangentially gripping the captured tree section as was the case for tangential abutment plate 82 . abutment plate 89 extends above knives 86 , substantially parallel to arms 52a , 52b and 54 ( fig1 ), approximately at the level of pivot axle 90 . preferably also , and as clearly illustrated in fig1 and 15 , the disc portion 86 of each jaw member 50a or 50b is convex relative to the underlying ground g . moreover , the semicircular peripheral section 86a of each jaw member 50a , 50b is made from two similar sections 110 , 112 taking in sandwich the peripheral edge of disk 86 . to immobilize the disc 86 edgewisely between the separate edge sections 110 , 112 , a bolt 114 anchors the latter edge sections to one another while the free edge of disc 86 engages a slanted peripheral groove 116 made on the inner portion of the underface of the upper edge section 110 , and with the lower edge section 112 being provided on the inner portion of its top face with a rounded peripheral ridge 118 engaging a correspondingly shaped groove 120 made on the underface of the peripheral edge section of disc 86 . edgewise section 110 is an integral portion of the bottom edge of the corresponding jaw supporting arm 88a or 88b , see fig1 . as best seen in fig2 and 8 , pivot mount 48 consists of a rigid casing 122 provided with a through pivot axle 124 . axle 124 pivotally engages through the rear wall 46b of the felling head frame 46 . casing 122 carries an upwardly forwardly inclined extension 126 , being endwisely connected to a substantially planar extension 127 of the rear edge of the frame top wall 46e , by a hydraulic ram 128 . more particularly , extension 126 includes a free end yoke 130 , carrying a transverse pivot axle 132 , pivotally mounted the piston rod end 134 of ram 128 , while extension 127 carries on its underface another yoke 136 with a transverse pivot axle 138 pivotally mounting the cylinder end 140 of ram 128 . axles 132 and 138 are parallel to one another and orthogonal to proximate casing wall 46b , for enabling limited roll motion of head 32 relative to boom 34 , as suggested by the angular sector of fig4 . it is envisioned that , in the felling head , the power means 128 , as well as 80 , 92 , 94 and 66 , 68 all be controlled remotely and individually by the truck operator inside cabin 36 , through hydraulic lines running along boom 34 in a conventional fashion . fig1 to 23 show how the knives 50a , 50b , the grabber arms 52a , 52b and the retaining lever 54 cooperate with one another during sequential cutting of the three upstanding trees . more than three upstanding trees can be captured , felled and retained per cycle of cutting , before unloading thereof is required . the total number of such trees in a single cutting cycle depends of course on the diameter of the trees and that of the loading area bounded by arcuate plate 82 and retaining lever 54 , until all of this available diametral tree collecting area 82 , 54 is tangentially occupied by the sectioned trees . the number of tree sections 42a &# 39 ;, 42b &# 39 ; 42c &# 39 ;, . . . are then carried by truck 30 rollingly through the forest toward a transport van ( not shown ), for releasing all the cut tree sections and unloading same thereon . the felling head can then be used for a second cycle of sequential tree cuttings . the grabber arms and retaining lever are preferably contoured to maximize the tree capturing capacity of the felling head . it is envisioned that , due to the special configuration of the various ram means on the felling head , the forces applied by the grabber arms are such that there results a very small structural strain is sustained by the felling head frame 46 . this in turn will promote longevity of the machine . outer lever 72 of retaining member 54 should be tapering towards its thin free end or &# 34 ; leading edge &# 34 ;, to facilitate its sliding displacement away from its position in between tree sections 42a &# 39 ; and 42 &# 39 ; b , see fig2 . returning to fig2 , it is clearly shown how the retaining lever 54 can release one ( or more ) captured tree section ( 42a &# 39 ;) even though an additional tree section 42b &# 39 ; has been captured by grabber arms 52a and 52b and is thus &# 34 ; in the way &# 34 ;. indeed , since the link between arms 70 and 72 of lever 54 is such that outer arm 72 may pivot inwardly toward inner arm 70 , albeit against the elastic bias of elastomeric band 78 , when releasing the captured tree 42 &# 39 ;. in this way , the outer arm does not need for its release to sweep as wide a circle of arc as it did when engaging the tree section captured by the grabber arms . thereafter , ( fig2 ) the lever member 54 is again pivoted inwardly to capture both tree sections , since the biasing strip 78 will have brought the outer leg of lever 54 to its normal position orthogonal to its inner leg . clearly , the release and engagement sequence illustrated in fig1 to 21 will apply whatever the number of cut trees already captured within the loading area . it is envisioned that the ram means of the pair of grabber arms and the ram means of the pair of knives be operatively connected to a common pair of hydraulic lines , in parallel , through t - couplings , i . e ., that a first hydraulic fluid hose from a first grabber arm ram means and a second hydraulic fluid hose from a first knife are connected to a first main fluid hose through a first t - coupling , and similarly , a third hydraulic fluid hose from a second grabber arm ram means and a fourth hydraulic fluid hose from a second knife are connected to a second main fluid line through a second t - coupling . in this way , the grabber arms , which are lighter in weight than the knives , will initially pivot yieldingly under the hydraulic fluid bias , exclusively of the knives , until a good , firm grasp of the upstanding tree is reached . from then on , the hydraulic fluid will apply the additional torque onto the knives while maintaining the initial torque onto the grabber arms . it is understood that , with such an arrangement , the torque applied by the grabber arms will be modulated as a function of the width of the upstanding tree selected for felling . indeed , the effort applied by the grabber arms tangentially to the registering section of tree , under the bias of the hydraulic fluid , will be substantially exactly the same , whatever the diameter of the selected tree ( within of course minimum and maximum limit tree diameters in relation to the overall structural dimensions of the grabber arms ). this constitutes a substantial improvement compared to existing felling heads , where the grabber arms had a &# 34 ; closed &# 34 ; position in which the distance between the two closed grabber arms was fixed , whatever the diameter of the selected tree . such prior art felling head grabber arms would therefore apply destructively high tangential forces onto a tree of large diameter , and not enough force onto a diametrally smaller tree , wherein only &# 34 ; average &# 34 ;, diameter size trees would be fully effective with these heads . indeed , prior art felling heads were prone to structural breaks under such strain , a major disadvantage . the present invention overcomes to a large extent such a problem , as disclosed hereinabove . finally , in the present invention , once the knives have fully cut the tree section , all the hydraulic fluid torque is transferred to the upwardly located grabber arms , to more firmly grip the cut tree section to prevent same from vertical tilting over the knives under its own weight .
a felling head for successively grabbing a number of upstanding trees , sequentially sectioning same , and capturing a number of sectioned tree sections one at a time to constitute a pack of sectioned tree sections held by the head , before it is required to unload the tree sections . the felling head has a ground - skimming horizontal knife that cuts trees , while a pair of upper grabber arms and a tree retaining lever capture that tree . the grabber arms then release the sectioned tree section , for engagement with a second upstanding tree , while the retaining lever retains the sectioned tree against the head .