NZ201760A - Tree felling head for mounting on carrier vehicle:circular saw has plate for supporting butt end of tree while cutting - Google Patents

Description

201760 Priority Date(s): .. I4k\ ?0- ir JM Complete Specification Filed: .... Class: falf&jfflt. & $ OCT 198S Publication Date: ............. .'.^V.

P.O. Journal, No: J.A.t.t.

NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION "TREE FELLING APPARATUS" F/We, FOREST ENGINEERING RESEARCH INSTITUTE OF CANADA, a Canadian Company, of 14 3 Place Frontenac, Pointe-Claire, Quebec, Canada, hereby declare the invention, for which £ / we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly described in and by the following statement:- (followed by page la) 20176 BACKGROUND OF THE INVENTION This invention is directed toward a method of felling a tree.

The invention is also directed toward a method for felling a stand of trees.

The invention is further directed toward felling apparatus for felling a teee.

The invention is also further directed toward felling equipment for felling a stand of trees.

Felling heads for felling trees are well known. The known felling heads in one embodiment employ shears to sever the trees to be harvested. The shears however must be quite thick in order to have the necessary strength to shear a tree. The thick shears compress the tree at the butt end while cutting it however and this compressive action can damage / the wood at, and adjacent, the butt end. If the tree is to be used to make lumber, the damaged portion of the tree at the butt end must be removed resulting in considerable waste.

Felling equipment employing shears is also relatively slow in operation. The felling head must be carefully positioned adjacent each tree so that the tree can be gripped before it is sheared. This positioning takes time. In addition, the actual acts of gripping and of shearing are relatively slow since they are hydraulic operations.

Another embodiment of known felling heads employs a chain-saw for severing a tree. Chain saws have several disadvantages however. They are slow cutting. With many moving parts, they require frequent main- 201760 tainence and lubrication. They also jam easily when encountering underbrush during tree severing. In addition, when using the chain saw, the tree must be securely gripped to minimize binding. This initial gripping action takes time thereby slowing the harvesting operation.

The present invention, in one embodiment, is directed toward providing a felling head with improved tree severing means. In accordance with the present invention, a felling head is provided with a circular saw at its bottom end, rotatable about a generally vertical axis, to cut a tree. The circular saw provides a fast, clean cut of the tree. The butt end of the tree is not damaged and the saw requires little maintainence. Most importantly, the tree can be cut without having to grip it prior to cutting thereby greatly speeding up the harvesting operation.

The felling head of the present invention employs means to grip a tree being harvested. However the gripping means are normally operated after the tree has been cut, and while the head is moving to the next tree being cut, thereby saving considerable time. The felling head also preferably employs collecting means which collects the trees as they are cut into a group which group can then be moved by the felling head to a storage location where they are unloaded. The felling head further includes means for minimizing the toppling of just cut trees, since they are not held during cutting.

The felling head of the present invention is employed with a carrier vehicle in a manner permitting a wide strip of trees to be harvested from a stand of 201/ trees in successive swaths across the strip. Harvesting the trees in swaths across a strip greatly improves productivity.

In one embodiment, the felling head is mounted on the end of a knuckle boom which in turn is pivotally mounted on a carrier vehicle. The boom is operated to swing the head across a strip in an arc, the head moved slightly back and forth across the arc by the boom and/or vehicle to delimit a swath and to pick up all the trees in the swath. Since the trees need not be gripped prior to severing, the head can be quickly moved to each tree, quickly severing it, and then gripping the severed tree while the head is moving to the next tree in the swath. Since the gripping action normally occurs during movement from one tree to the next, the speed of the harvesting operation is quickly increased.

It is known to use circular saws in harvesting equipment. Canadian Patent 1,029,283 by way of example shows the use of a circular saw on a carrier vehicle. This equipment however is only good for cutting a very narrow strip of trees from a stand since the saw is fixed on the vehicle and is not mounted on a movable felling head. In addition, separate equipment must be employed to gather the cut trees.

The present invention is broadly directed toward an apparatus for felling a tree, comprising a circular saw for cutting through the tree, and gripping means for clasping the tree substantially immediately after it has been cut through, the gripping means being adapted to hold the severed tree in a standing position. 201760 The invention is also broadly directed toward a method of felling a tree including the steps of cutting through the tree with a circular saw and substantially immediately after the tree has been cut through, clasping the tree by use of gripping means adapted to hold the severed tree.

SUMMARY OF THE INVENTION The present invention is particularly directed toward a tree felling head adapted to be mounted on a carrier vehicle. The head has a main frame, and a circular saw to cut trees mounted at the bottom end cf the main frame for rotation in a plane generally parallel to the ground when the head is mounted on the vehicle. Means are provided to rotate the saw. Means are further provided on the main frame for gripping a tree after it. has been cut by the saw.

In a more specific embodiment means are also provided just above the saw for supporting the butt end of a cut tree.

The invention is further directed toward felling equipment employing the above felling head. The felling equipment includes a carrier vehicle, the felling head, and means connecting the felling head to the vehicle in a manner that the felling head can be moved in a swath transversely across a strip of tress to be cut.

. The invention is also directed toward a method for felling a tree using the felling head which comprises the'steps of moving the head adjacent the tree to have the saw cut through the tree, letting the butt end of the cut tree drop on the butt end supporting 201760 means, and gripping "the cut tree while on the butt end supporting means.

The invention is still further directed toward a method for using the felling equipment which comprises moving the felling head in a swath across a strip of trees to be cut and cutting through each tree encountered in the swath with the circular saw. The butt end of each cut tree is allowed to drop onto the butt end supporting means after which the cut tree is gripped.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of th? felling heads Fig. 2 is a partial cross-section view of the felling head; Fig. 3 is a side view of felling equipment employing the felling head; Fig. 4 is a plan view of the felling equipment in operation; and Fig. 5 is a plan view of another embodiment of the felling equipment.

DESCRIPTION OF THE PREFERRED EMBODIMENT The tree felling head 1 of the present invention, as shown in Fig. 1, has a main frame 3. Support means are provided on the bottom end of the main frame 3* The support means includes means 5 for supporting a circular saw 7 on the frame 3 and means 9 for supporting the butt end of a tree cut by the saw just above the saw 7- The saw support means 5 comprises a circular support plate 11 mounted on the bottom end of the main frame 3. The plate 11 extends 201J6 "transverse to the main frame 3» A cut-out i-3 extends inwardly from the peripheral edge 15 of the plate 11 towards its center, on the side of the plate dpposite to the main frame 3 connection. The cut-out dj is generally U-shaped and can extend through an arc encompassing between and 90 of the periphery of the plate.

The circular saw 7 is mounted beneath the support plate 11 and parallel to it. The saw 7 is rotated about an axis 17 which extends transverse to both it, and support plate 11, by a motor 19 mounted on top of plate 11. A drive shaft 21 extends from motor 19 beneath plate .11 as shown in Fig. 2. A collar 23» fixed on the center of the top side 25 of saw 7, receives the end of drive shaft 21. Means (not shown) detachably connect the collar 23 to the drive shaft 21. The saw 7 is slightly smaller in diameter than the diameter of the support plate 11. A protective skirt 27 extends down from the peripheral edge 15 of the plate 11 -co just below the saw 7.

The means 9 on the felling head for supporting the butt end of a cut tree comprises a butt plate 29 mounted to support plate 11 in the cut-out 13. The butt plate 29 is located parallel to, and closely adjacent to, the top side 25 of saw 7, below the level of support plate 11. The butt plate 29 also lies close to but does not cover the saw teeth 31. Side plates 33 connect the inner edge 35 of butt plate 29 to the edge 37 of support plate 11 defining cut-out 13.

The felling head 1 includes tree holding means 4-1 mounted on the frame 3 above the support plate .11. The tree holding means *fl comprise a pair of curved 201760 arms 43 each pivotally mounted on a pivot pin 45 carried by frame 3. The pins 45 extend parallel to each other and to saw axis 17- Means (not shown) are provided for moving the arms 43 toward each other to overlap and cross to hold a tree between them.

The felling head 1 also preferably includes tree collecting means 51* The tree collecting means 51 comprise a pair of curved arms 53# each mounted by a pivot pin 55 to the end of a short straight arm 57 which in turn is mounted at its other end by a pivot pin 59 to frame 3- Pivot pins 55» 59 extend parallel to pivot pins 45• Means (not shown) are provided for moving the arms 43 and 53 toward each other to hold a plurality of cut trees. Both the tree holding means 41 and the tree collecting means 51» and their operation, are well known in the art.

Felling head 1 further includes means 61 at the top end of the frame 3 "to minimize the tendency of a just-cut tree to topple off the butt plate 29. These means 61 can comprise a support bar 63 extending inwardly from the frame 3 and having a concave surface 65 facing generally in the same direction as the cutout 13. The surface 65 is located between axis 17 and frame 3 and a just-cut tree, while resting on butt plate 29» willimove toward surface 65 as the head moves forward and will lean against surface 65 to prevent the tree from toppling off plate 29. The height of frame 3 can be extended as compared to the height of frames in known felling heads so as to locate the support bar 63 further above the butt plate 29, and thus further minimize toppling. 201760 The felling head 1 includes means 71 on the frame 3 for use in attaching the apparatus to a carrier vehicle. These means 71 can comprise an attachment bracket 73 which extends rearwardly from the frame 3 generally midway between its ends.

The felling head 1 forms part of felling equipment 79 and is mounted on a carrier vehicle 81 using bracket 73 as shown in Fig. 3. The carrier vehicle 81 preferably carries a knuckle boom 83 which is mounted on a base 85 rotatable about a pivot 87 mounted on the vehicle body 89- An operator's cab or station 91 is mounted on base 85 adjacent boom 83. The base 85 carries the power unit 93 for providing power to operate the boom 83 and the felling head 1. The felling head 1 is mounted via bracket 73 on the outer end 95 of the other arm 97 of boom "83. Conventional hydraulic means 99, 101, 103 are used to move the felling head 1 relative to the outer arm 97, the outer arm 97 relative to the inner arm 105, and the inner arm 105 relative to the base 85. respectively, as is well known. The operation of one or more of the hydraulic means 99, 101, 103 will move the felling head 1 with the saw 7 close to the ground to cut trees within the inner and outer range of the boom 83. The boom can be moved to move the felling head 1, or more particularly the saw 7 either in a shallow arc, close to the ground, or parallel and close to the ground.

As shown in Fig. 4 the boom 83 is rotated to one outer edge 109 of a strip 111 of trees 113 to be harvested from a stand 115 by rotating base 85 on the vehicle body 89* The boom 83 is then swung across 201760 the strip 111 to the other outer edge 11? of the strip moving the felling head 1 generally in an arc 119 across the strip 111. The head 1 is moved slightly forwardly or rearwardly to pick up each tree in or adjacent the arc by actuating any or all of the boom hydraulic acutating means 99» 101, 103 to thereby cut a swath 121 across the strip 111. As the head 1 encounters each tree 113» "the circular saw 7» projecting past butt plate 29. cuts through the tree close to the ground. The teeth 31 on the saw 7 are set to produce a wide kerf 123 through the tree as shown in Fig. 2 so that the butt plate 29# closely adjacent the teeth 31 on the saw 7» and the side 25 of the saw, can move into the kerf 123 as the saw cuts through the tree. In addition, the wide kerf 123 minimizes binding if the saw is not quite parallel to the ground while cutting. During cutting of the tree, the tree is not held. As. a result, the tree is cleanly cut through with little or no damage to the butt end 125- Once the tree is cut through it drops a very short distance onto the butt plate 29 while support bar 63 prevents the tree from toppling. While moving the boom 83 to swing the saw 7 to the next tree, the cut tree is gripped by the gripping means 41 and the collecting means 51 are actuated to hold the tree along with other trees already cut. The next tree is cut in a similar fashion as are the other trees encountered in the swath 121 travelled by the head 1. Once the head reaches the other side 117 of the strip 111, the head is swung back to the one side 109» advanced slightly either by extending boom 83, or by advancing the vehicle 81 and a next 201760 swath 121 is cut across strip 111 by head 1 to cut the trees encountered in this next swath.

The above method of tree cutting is extremely fast. Since the trees need not be held for cutting, no time is wasted prior to cutting in gripping the trees. Also, since the trees need not be held during cutting, the butt ends are not damaged. The swing movement permits a wide strip to be quickly cut in swaths with little wasted motion of the equipment. Often, more than one small tree can be cut, if the trees are close together before the gripping means need be actuated.

Once the collecting means 51 are full of trees, the head 1 is positioned by the boom 83 at an unloading station and the collecting means 51 are opened up to unload the collected group of trees. ' While the felling head 1 has been shown mounted on the end of a knuckle boom 83, it can also be mounted via a bracket 133 on a cross-bar 135 extending transversely across tha front of a vehicle 137. Means 139. such as a cable drive, are provided for moving the felling head 1 transversely across the front of the vehicle on the cross-bar 135» cutting a straight swath 141 across a strip 143 of trees.

Means 145 can be provided for moving the cross-bar 135 rearwardly and forwardly relative to the vehicle to cut all the trees 113 in the swath 141, or for moving the vehicle back and forth to cut the trees in the swath 141. The head 1 can be rotatably mounted on the cross-bar 135 to unload collected trees on one side of the strip 143. Other unloading means can be employed. 2017 The felling head 1 can be mounted on other types of booms as well other than knuckle booms provided they they can move to traverse a strip.

Claims (17)

201760

1. A tree felling head for mounting on a carrier vehicle in a manner that the felling head can be moved transversely, forwardly and rearwardly, the felling head having: a main frame, a circular saw to cut trees; means for fixedly mounting the saw on the main frame where it can be positioned, by movement of the felling head, in a plane substantially parallel to the ground; means for rotating the saw; and means operatively connected to the main frame for gripping a tree above the butt end after the tree has been cut by the saw by moving the felling head while the saw is rotated.

2. A felling head as claimed in claim 1 including means mounted on the main frame just above the saw for supporting the butt end of a cut tree thereon.

3. A felling head as claimed in claim 1 having a butt plate mounted on the main frame just above the saw for supporting the butt end of a cut tree thereon, the butt plate covering a portion of the saw, but not covering some of the saw teeth.

4. A felling head as claimed in claim 1 including means on the main frame adjacent the gripping means for collecting a group of cut trees.

5. A felling head as claimed in claim 1 including fixed support means on the main frame above the gripping means for use in minimizing the tendency of a cut tree to topple.

6. A felling head as claimed in claim 1 having a butt plate mounted on the main frame just above the saw for supporting the butt end of a cut tree thereon, the butt plate covering a portion of the saw excluding the saw teeth. -12- ?8juumi

7. A felling head as claimed in claim 1 including 201760 frame for mounting the felling head on an extensible, laterally swingable boom on a carrier vehicle.

8. A felling head as claimed in claim 1 wherein the main frame has an upper and a lower part, the upper part having at least one support on the lower part of the main frame; a butt plate mounted on the lower part of the main frame just above the saw for supporting the butt end of a cut tree thereon; the teeth on the circular saw extending beyond the periphery of the butt plate; and the leading edge of the saw projecting beyond the location of the support by a distance such that a the tree comes into contact with any other part of the felling head except the butt plate.

9. A method of felling a tree with a felling head having a frame with a circular saw fixed to the frame, means on the frame for rotating the saw, and means on the frame for gripping a cut tree; the method including the steps of: cutting through the tree with the circular saw by moving the felling head while rotating the saw, and substantially immediately after the tree has been cut through, clasping the tree by the use of the gripping means to hold the severed tree.

10. A method as claimed in claim 9 wherein the saw is fixedly mounted on a felling head, and the felling head is moved while the saw is rotated thereon to have the saw cut through the tree.

11. A method as claimed in claim 10 wherein the cut tree is supported on a butt plate while being clasped.

12. A method as claimed in claim 10 including the additional step of collecting cut trees in a group on the felling head. to contact an upright severed tree; the circular saw mounted tree being felled can be cut through by the saw blade before -13- 201.760

13. A method as claimed in claim 10 wherein the felling head is moved transversely across a plurality of trees to be cut to position the head at each tree, and forwardly to cut each tree.

14. A method as claimed in claim 10 wherein the felling head is posi- before the tree is cut.

15. A method as claimed in claim 10 including the step of supporting the cut tree on a butt plate and then clasping it.

16. A method of felling a tree substantially as herein described with reference to the accompanying drawings.

17. Apparatus for felling a tree substantially as herein described with reference to the accompanying drawings. tioned to locate the saw in a plane transverse to the tree I'3 <''e . .f By fcWs/Thsir Authorised Agents, A. J. PARK & SON -14-