TREE HARVESTER

Abstract: A tree harvester (10) has a main boom (20) pivotally mounted on the front section (17) of the chassis, the rear section (11) carrying the power unit for the harvester. A secondary boom is telescopically mounted in the main boom (20) and has a grapple and shear assemblies (15, 16) to grip and sever two trees, which are de-limbed by de-limbing knives provided on a de-limbing trolley (79) which moves along a de-limbing gantry (73) simultaneously as the gantry (73) moves along the main boom (20). Docking knives on the de-limbing trolley (79) dock the waste timber from the tops of the trees. A shear assembly in which shear blades move from open to closed position to sever a tree with the cutting edges of the blades being maintained in a parallel relationship and a grapple support assembly in which a grapple assembly is operable to move to engage and grip trees between a vertical and an horizontal attitude are also enclosed and separately claimed.

Description: TITLE: "TREE HARVESTER" BACKGROUND OF THE INVENTION (1) Field of the Invention This invention relates to tree harvesters. (2) Description of the Prior Art International Application No. PCT/AU80/00102 (International Publication No. WO81/01496) filed in the name of GEMMELL-MURDOCH, Andrew (and now assigned to ourselves) disclosed a tree harvester which enabled two trees to be de-limbed simultaneously. The harvester described in that application incorporated a main boom on the machine; a secondary boom, supporting the grapple and shear assembles, telescopically mounted on the main boom; and a de-limbing assembly movably mounted on t e main boom and operable so that as the secondary boom is extended forwardly, the de-limbing head moves rearwardly along the main boom at approximately the same speed. This harvester has proved to have considerable advantages over previously known machines (examples of which include those described in Canadian Patent Nos. 1,046,908 and 1,051,756 of Eaton Yale Ltd; U.S. Patent No. 3,905,407 assigned to Clark Equipment Co.; Australian Patent No. 496860 of Eaton Yale Ltd.; and Australian Patent Nos. 474858 and 475520 of R.L. Windsor & Son Pty. Ltd.). However, it is considered that a number of improvements can be made to that harvester. On that harvester, the secondary boom is extended e.g. 2-4 metres, to enable a length of e.g. 4.8 metres to be de-limbed in each de-limbing operation. In certain applications it is considered that this forward extension places the weight of the trees too far forward of the centre of gravity of the harvester, unbalancing it. In another area, it has been found that where the grapples are holding two trees of markedly different / diameters, the smaller tree may not be on the bottom knives of the de-limbing head,reducing the effective¬ ness of the latter. It is also considered that the scissor-type 5 action of . the shearing head does not cut the trees as cleanly as possible, especially when docking the trees to length. In addition, the limited movement of the shear and grapple heads relative to the machine does not 0 enable the harvester to harvest trees which have fallen or leaning away from the harvester . Finally, when de-limbing the upper sections of the trees, these sections are often not strong enough to enable the trees to be fed through the shear and 5 grapple heads to enable them to be docked to length and - so one length of timber from each tree may be wasted. SUMMARY OF THE PRESENT INVENTION It is an object of the present invention to provide a boom assembly for tree harvesters where the 0 secondary boom supporting the grapple assembly does not have to be extended forwardly the same distance as the de-limbing assembly moves rearwardly. It is a preferred object of the present invention to provide a grapple assembly where the grapples are so 5 arranged that the grapples align the centres of both trees in the same plane regardless of their respective diameters, so that both trees will be supported by the base plate of the de-limbing head. In a further preferred embodiment, the shears in 0 the shearing head are fully floating and mounted on parallelogram-type links so that they cut transversely to the axis of the shears. In a still further preferred embodiment, the shearing and grapple- assembly are mounted on a support 5 assembly which enables the assemblies to cut trees which are lying down or inclined longitudinally or laterally relative to the machine. In a still further preferred embodiment, the grapple assembly is operable to lift delimbed trees and deposit them on a stack. Other preferred objects of the present invention will become apparent from the following description. In one aspect the present invention resides in a tree harvester including: a main boom mounted on a prime mover; a secondary boom telescopically mounted on the main boom and supporting a grapple assembly for gripping a tree trunk and a shear assembly for severing a tree trunk; a de-limbing gantry movably mounted on the main boom; a de-limbing assembly movably mounted on the de- limbing gantry; means to extend or retract the secondary boom relative to the main boom; means to move the de-limbing gantry relative to the main boom; and means to simultaneously move the de-limbing assembly along the de-limbing gantry as the de-limbing gantry is moved relative to the main boom. Preferably the means to move the secondary boom and the de-limbing gantry include respective hydraulic rams mounted on the main boom. Preferably the means to move the de-limbing assembly (having a de-limbing head) includes a pair of cables, each fixed at one end to the de-limbing assembly and at the other end to the main boom and passing around respective pulleys at opposite ends of the de-limbin gantry. In a second aspect, the present invention resides in a shear assembly for a tree harvester, including: o...? a shear support frame; a pair of shear arms each having a shear blade; respective pairs of parallelogram links pivot¬ ally mounting each shear arm on the support frame; and means interconnecting a respective link on each shear arm adapted to move the shear blades from an opened position to a closed position to sever a tree, the cutting edges of the shear blades being maintained in a substantially parallel relationship. In a third aspect, the present invention resides in a grapple support assembly for a tree harvester including: a first support member pivotally mounted on a boom.; a second support member pivotally mounted on the first support member for movement in a plane substantially along the longitudinal axis of the harvester; a grapple assembly mounted on the second support member; and means interconnecting the first and second suppor members and operable to move the second support member to enable the grapple assembly to engage and grip trees between a substantially vertical and a substantially horizontal attitude. Preferably the first support member is pivotally mounted on the boom for pivotal movement in the same plane as the second support member. Preferably the first and second support members are operable to lift delimbed trees from the de-limbing assembly and deposit them on a stack. Preferably the grapple assembly has inner and outer grapple arms to selectively grapple the first and second trees, respectively, to be harvested. Preferably the inner and outer grapple arms each have a grapple arm pivotally mounted about a common pivot point which form a common apex ensuring the trees are aligned in the grapple assembly. Preferably one of each grapple arm pair is bifurcated and co-operates with the other arm of the pair to engage the respective tree at three points to securely grip the tree. BRIEF DESCRIPTION OF THE DRAWINGS To enable the invention to be fully understood, a preferred embodiment will now be described, by way of illustrative example only, with reference to the accomp¬ anying drawings, in which: FIG. 1 is a side view of the tree harvester with the grapple- and shear assemblies in their tree severing position; FIG. 2 is a plan view corresponding to FIG. 1; FIG. 3 is a plan view of the shear assembly in its open position; FIG. 4 is a plan view of the shear assembly in its closed position; FIG. 5 is a plan view of the tree harvester showing the grapple - and shear assembles turned to one side intermediate their tree severing and their de-limbing position; FIG. 6 is a side view of the harvester showing the grapple - and shear assemblies raised to their de- limbing position during the de-limbing operation; FIG. 7 is a side view of the harvester showing the grapple- and shear assemblies in their lowered position to pick up and sever fallen trees or for placing trees on stack; FIG. 8 is a sectional front view of the main boom and the de-limbing head taken on line 8-8 on FIG. 7; and FIGS. 9, 10 and 11 show the steps of the de- limbing operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The tree harvester has an articulated prime mover 10. The power unit in the rear section 11 of the harvester contains the engine and hydraulic pumps which power the harvester, while the operator's cabin 12, the boom assembly 13, de-limbing assembly 14, and grapple- and shear- assembles 15, 16 are mounted on the front section 17. The hubs 18 of the ground wheels 19 are provided with hydrostatic motors (not shown) and the articulated steering is provided by hydraulic rams 20. The boom assembly 13 includes a main boom 21, of substantially box section, mounted on transverse brackets 22 pivotally mounted on a longitudinal pin 23 fixed in the end plates 24 of a support box 25, this box being pivotally mounted on the front section 17 via transverse trunnions 26. Rams 27 (interconnecting the support box and the front, section) and 28 (interconnecting the support box and the transverse brackets) are operable to respectively raise and lower, or tilt, the boom assembly 13 relative to the harvester 10. A secondary boom 29, also of box section, is telescopically mounted in the main boom 21 and is supported by spaced support rollers 30 provided at the front of the main boom 21 and by upper and lower rollers 31 on the rear end of the secondary boom. A hydraulic ram 32 is fixed in the secondary boom 29 and engages a flange 33 in the main boom 21, operation of the ram extending and retracting the secondary boom. A transverse beam 34 is fixed on the forward end of the secondary boom and extends laterally of the front of the harvester. A support block 25 is mounted centrally on the rocket arm. The support assembly from the grapple- and shear OMPI assemblies 15, 16 includes an outer support member 36 which is substantially L-shape in side view. The support member has a pair of parallel vertical side plates 37 which are pivotally interconnected at their upper ends to the support block 25 via a pivot pin 28. A leg member 39 extends forwardly of the lower end of each side plate 27 and the leg members are interconnecte by a transverse pivot pin 40 at their free ends. A hydraulic ram 41 (see FIG. 6) interconnects the support block 25 and the outer support member 36 and is operable, by retraction or extension, to raise or lower the support member. The inner support member 42 is substantially C-shape in side view and has a lower leg 43 pivotally mounted on the pivot pin 40 adjacent its forward end. The upper leg 44 is connected to the lower leg 43 by a curved spine 45. A hydraulic ram 46 is provided between the curved spine 45 and the outer support member 36, retraction of the ram 46 moving the inner support member 42 to the inclined position shown in FIG. 7, while extension of the ram moves the inner support member to a substantially upright position (as shown in FIG. 1) . A main pivot and support pin 47 interconnects the free ends of the lower leg 43 and the upper leg 44. Referring now to FIGS. 2 and 5, the grapple assembly 15 has a bottom support plate 48 and a top support plate 49, the support pin 47 extending through both plates. The grapple assembly has two spaced pairs of inner grapple arms 50 and two spaced pairs of grapple arms 51, the inner and outer grapple arms respectively gripping the first and second trees harvested. One of the inner grapple arms 50a is mounted on a pivot pin 52 provided between the bottom - and top __OMPl , support plates 48, 49. The other grapple arm 50b of the pair is pivotally mounted on a similar pivot pin 53. However, this arm is bifurcated so that the first tree is gripped at three points between the pair of 5 arms 50a, 50b. Extensions 54 on the arms are inter¬ connected by a hydraulic ram 55 which is extended to cause the tree to be gripped by the arms. One outer grapple arm 51a is also mounted on pivot pin 52 while the other arm 51b, which is also bifurcated, is mounted 0 on the support pin 47. Extensions on the arms are inter¬ connected by a hydraulic ram 56 which is extended to cause the second tree to be harvested to be gripped by these arms. The centres of the trees gripped in the grapple 5 assembly 15 are aligned as the centres o_f the trees and the respective pivot points of the inner and outer grapple arms form respective triangles which has a common apex on pivot pin 52. The shear assembly 16 (see FIGS, 3 and 4) has 0 top and bottom support yokes 57 pivotally mounted on the main pivot and support pin 47. A pair of rocker links 58 are pivotally mounted intermediate their lengths on pivot pins 59 fixed at the forward free ends of the arms 60 of the support yokes 57. 5 Each shear arm 61 has a replaceable shear blade 62 with a linear cutting edge 63. Each shear arm is pivotally mounted on the forward end of a respective rocker link 58 via pivot pin 64 which passes through a central lug 65 on the shear arm. 0 Secondary links 66 pivotally interconnect rearward lugs 67 on each shear arm to corresponding lugs 68 on the yokes 57 via pivot pins 69, 70. As shown, the pivot pins 59, 64, 69, 70 for each shear arm are arranged at the corners of a parallelogram. 5 When the hydraulic ram 72 interconnecting the rearward free ends of the rocker links 58 is extended, the shear arms 61 are moved towards each other with their cutting edges 63 parallel. A delimbing gantry 73 is movably mounted on the main boom 21 and has a pair of side plates 74 (of inverted L-section in end view) connected to a top plate 75 by vertical webs 76. Rollers 77 on the main boom 21 run in the tracks 78 formed along the gantry to support the latter, while the gantry is stabilized by suitable stabilizing rollers (not shown) . A hydraulic ram (not shown) is mounted in the main boom 21 and is connected to the gantry 73 so that extension of the ram moves the gantry rearwardly along the boom for a distance of, for example, 1.8 metres. A delimbing trolley 79, having a double delimbing head 80, is movably mounted on the gantry 73 by rollers 8 running in tracks 82 along the latter. A pulley and cable assembly 83 interconnects the main boom and delimbing trolley to move the latter along the gantry as the gantry moves along the main boom in a similar manner to the method disclosed in International Application No. PCT/AU80/00102. Therefore, the movement of the gantry relative to the main boom is multiplied so that the delimbing trolley moves at twice the velocity relative to the boom. The delimbing head 80 has three spaced base plates 84, the rearward pair of which are provided with opposed delimbing knives 85 operated by a ram 86. Docking knives 87, provided with a ram 88, are pivotally mounted on the forward base plate to sever trees up to a diameter of, for example, lOcm. The operation of the harvester will now be describe . The secondary boom 29, gantry 73 and delimbing trolley 79 are positioned as shown in FIG. 1; the outer OMPI , and inner support members 36, 42 raised so that the pivot pin 47 is substantially vertical and the grapple and shear assemblies 15, 16 are opened. The operator approaches a tree to be harvested 5 until the tree is positioned between the shear arms 61. By operating the rams 41 and/or 46 (and, if necessary, the rams 27 and 28) he tilts the grapple and shear assemblies 15, 16 until the tree trunk lies between the inner grapple arms 50. He operates the ram 55 to cause lυ the grapple arms 50a, 50b to move inwardly until the tree is gripped between the arms. He extends the ram 72 to cause the shear arms 61 to move inwardly, the shear blades 62 severing the tree trunk adjacent its base. He retracts the rams 72 to open 15 the shear arms and approaches a second tree until the latter lies between the outer grapple 51, the operator having aligned the grapple and shear assemblies with the second tree trunk. He extends ram 56 which moves the outer grapple arms 51, 51b towards each other to grip 20 the tree. In this position, the centres of the trees are aligned. The operator extends the ram 72 to sever the second tree trunk. The outer- and inner support members 36, 42 are 25 brought to their upright positions and the grapple and shear assemblies 15, 16 are swung through 90° by a ram (not shown) to the position shown in FIG. 5 and then the outer support member 36 is then raised by ram 41 so that the trees rest on the base plates 84 of the 30 delimbing head 79. The delimbing knives 85 are closed around the trees. The secondary boom 29 is extended, e.g. 1.2 metres, and the gantry 73 moved rearwardly, e.g. 1.8 metres, simultaneously moving the delimbing trolley 79 35 along the gantry 73 a distance of 1.8 metres, so that a total length of 4.8 metres of the trees is delimbed. The grapples and shears are opened and the secondary boom and gantry retracted so that 4.8 metres of delimbed timber is moved past the shear arms 61, the delimbing knives 85 having been clamped about the trees. The shear arms 61 are closed and this length of delimbed timber is docked from the trees. The grapples and shears are closed and the delimbing knives returned to their delimbing mode and 0 the operation is repeated to delimb and dock successive 4.8 metre lengths from the trees. When the last useful 4.8 metre section of trees has been delimbed, the operation is modified. The operator retracts the secondary boom. The * 5 distance from the shear blades to the front of the boom is now 1.2 metres, and the distance from the docking knives 87 to the front of the boom is 3,6 metres (the gantry remaining extended and the delimbing trolley at the end of its travel) . 0 The docking knives 87 are closed and the waste timber is docked from the tops of the delimbed trees. The delimbing knives 85 are opened, the outer support member 36 is lowered (to the position shown in FIG, 7) and the inner support member 42 swung forwardly 5 (also as shown in FIG. 7) until the trees lie substant¬ ially horizontal forwardly of the harvester. The grapples are released and the trees are deposited on a stack. As the secondary boom can be extended independent ly of the gantry r the boom may be extended to enable the operator to reach between trees to grip and sever a tree that he could not otherwise reach. The grapple- and shear assemblies can be set to grip and sever trees at almost all attitudes, which is particularly important when harvesting trees lying down or on hillsides. OMPI The operation of the secondary boom, the gantry and the delimbing trolley relative to the main boom enable the whole assembly to be more compact than the boom assembly disclosed in International Application No. PCT/AU80/00102 without any reduction in the length of timber which can be delimbed and docked. It will "be readily apparent to the skilled addressee that many changes and modifications may be made to the embodiment described and illustrated without departing from the present invention. For example, the hydraulic controls for the delimbing knives, and the grapple and shear arms may include circuits which ensure that while the delimbing knives grapple the trees, the " grapple and shear arms are placed in delimbing mode, and vice versa.

Claims: CLAIMS : 1. A tree harvester including: a main boom mounted on a prime mover; a secondary boom telescopically mounted on the main boom and supporting a grapple assembly for gripping a tree trunk and a shear assembly for severing a tree trunk; a de-limbing gantry movably mounted on the main boom; a de-limbing assembly movably mounted on the de-limbing gantry; means to move the de-limbing gantry relative . to the main boom; and means to simultaneously move the de-limbing assembly along the de-limbing gantry as the de-limbing gantry is moved relative to the main boom. 2. A tree harvester as claimed in Claim 1 wherein: the means to move the secondary boom and the de-limbing gantry relative to the main boom include independently operable hydraulic rams on the main boom; and the means to move the de-limbing assembly along the de-limbing gantry includes a pair of cables, each fixed at one end to the de-limbing assembly and at the other end to the main boom, the cables passing around respective pulleys at opposite ends of the de¬ limbing gantry. 3, A tree harvester as claimed in Claim 1 or Claim 2 wherein: the de-limbing assembly includes a de-limbing trolley mounted on rollers running in tracks on the de¬ limbing gantry; and a de-limbing head on the trolley having a plurality of base plates to support a tree trunk or trunks to be de-limbed and a plurality of co-operating de-limb¬ ing knives operable with the base plates to de-limb foliage from the tree trunk or trunks as the de¬ limbing trolley is moved along the de-limbing gantry. 4. A tree harvester as claimed in any one of Claims 1 to 3 wherein the shear assembly includes: a shear support frame mounted on the secondary boom; a pair of shear arms each having a shear blade; respective pairs of parallelogram links pivotally mounting each shear arm on the support frame; and means- interconnecting a respective link on each shear arm adapted to move the shear blades from an opened position to a closed position to sever a tree, the cutting edges of the shear blades being main¬ tained in a substantially parallel relationship. 5. A tree harvester as claimed in Claim 4 wherein: the respective link on each shear arm includes a rocker arm pivotally mounted intermediate its length on the shear support frame, the respective shear arm being pivotally mounted at one end of the rocker ram; and the means interconnecting the respective link includes a hydraulic ram. 6. A tree harvester as claimed in any one of Claims 1 to 5 wherein the grapple assembly is mounted on a grapple support assembly on the secondary boom, the grapple support assembly including: a first support member pivotally mounted on the secondary boom; a second support member pivotally mounted on the first support member for movement in a plane sub¬ stantially along the longitudinal axis of the main boom, the grapple assembly being mounted on the second support member; and OM means interconnecting the first and second support member and operable to move the second support member to enable the grapple assembly to engage and grip trees between a substantially vertical and a substant¬ ially horizontal attitude. 7. A tree harvester as claimed in Claim 6 wherein: the first support member is pivotally mounted on the secondary boom for movement in the same plane as the second support member to enable trees gripped by the grapple assembly to be placed on the de-limbing - assembly for de-limbing of unwanted foliage. 8. A tree harvester as claimed in Claim 6 wherein the grapple assembly includes: a grapple support pivotally mounted on the second support member to enable the grapple assembly to be swung transversely to the secondary boom; respective first and second pairs of grapple arms pivotally mounted on the support; respective means to move the pairs of grapple arms between respective open released positions and closed, gripping positions, wherein: one of each pair of grapple arms is pivotally mounted on a common pivotal axis; the other of. each pair of grapple arms are pivotally mounted about respective pivotal axes, so arranged that in the closed position, the engagement of the grapple arms with the tree trunks gripped by the grapple arms and the respective pivotal axis of the grapple arms align the tree trunks relative to the secondary boom. 9. A tree harvester as claimed in any one of Claims 1 to 8 wherein: a support box is pivotally mounted on trunnions on the prime mover transverse to the longitud¬ inal axis of the main boom; O P the main boom is pivotally mounted on trunnions on the support box parallel to the long¬ itudinal axis of the main boom; and respective means are provided to pivotally move the support box and main boom to raise and lower and/or tilt the main boom relative to the prime mover. 10. A shear assembly for a tree harvester including: a shear support frame; a pair of shear arms each having a shear blade; respective pairs of parallelogram links pivot¬ ally mounting each shear arm on the support frame; and means interconnecting a respective link on each shear arm adapted to move the shear blades from an opened position to a closed position to sever a tree, the cutting edges of the shear blades being maintained in a substantially parallel relationship. 11. A grapple support assembly for a tree harvester including: a first support member pivotally mounted on a boom; a second support member pivotally mounted on the first support member for movement in a plane sub¬ stantially along the longitudinal axis of the harvester; a grapple assembly mounted on the second support member; and means interconnecting the first and second support members and operable to move the second support member to enable the grapple assembly to engage and grip trees between a substantially vertical and a substantiall horizontal attitude. O

Inventors: GEMMELL-MURDOCH ANDREW, GEMMELL-MURDOCH, ANDREW
Applicants: MURDOCH LOGGING IND, MURDOCH LOGGING INDUSTRIES PTY. LTD.
Application year: 1983
Main classification: A01G23
IPC codes: A01G23